Making a complicated dessert once in a while is a good way to practice a lot of techniques and to learn something new. The French in particular are good in making pastry which consists of a lot of different (complex) components. That said, this Italian creation, the Torta Settevelli (cake with seven layers), also brings together a lot of techniques and thus science! Cake, cream, mousse and a glaze all pass by.
You can find the recipe at the bottom of the post, but we are going to take the opportunity to evaluate some of its components in more detail first.
What is a torta settevelli?
A Torta Settevelli is an Italian cake made up of seven layers: 2x chocolate cake, 2x hazelnut cream, 1x hazelnut crunch, 1x chocolate mousse and 1x mirror glaze (although various variations float around).
At the bottom of this post you can find a recipe (be aware, this is a multi hour project if you make it at home). What we’re mostly interested in though, is to learn how the different components work and why they work the way they do. It’s a good chance to apply some of our science to a recipe!
Origin stories of dishes are often hard to trace back, but this is an exception, mostly thanks to the fact that it’s a pretty recent creation! It seems to have been developed by Italian chefs during a baking competition, in the 1990s. (Great British Bake Off says it is a traditional birthday cake, but I’m a bit doubtful of that.) You will find very similar looking cakes in Italy with a slightly different name, apparently because the original name is trade marked by the original chefs.
The challenges of a torta setteveli
Seeing as how it as created during a competition, it is quite a complex cake, but one that comes together really nicely. Seeing that there are 5 different layers time management is the main challenge of this cake. Apart from that, there are several techniques you should be able to execute/will be able to practice (in the order of appearance in the recipe):
- Roasting hazelnuts
- Caramelizing sugar
- Grinding nuts to make a paste
- Make an anglaise
- Use gelatin to stabilize a cream
It so happens, we’ve written extensively about each of these before! Here’s a short recap with links to the other articles so that at the end of this you can both bake the cake and explain to others all the fascinating science behind the cake!
Apart from these more specific techniques, you will need to bake a cake and make a chocolate mousse. The cake is a pretty simple one (with somoe similarities to a Genoise). The chocolate mousse only contains two ingredients: chocolate & cream. you might wonder how hat mousse stays stable over time? Well, the chocolate hardens when it cools down, keeping the whole mousse in place!
Nuts naturally contain a lot of fats, proteins and a little sugar. Nuts are flavoursome by themselves, however, there is potential for a lot more flavour! When you heat the nuts a lot of chemical reactions occur, collectively called the Maillard reaction. These reactions cause browning of the nuts but they also give the nuts a lot of extra flavour. This roasted flavour really enriches anything made with them. Of course, the trick is not to burn the nuts or there nice flavours get overpowered by the burned ones.
If there’s a cooking skill that really is a food chemistry experiment, it’s caramelizing sugar. When you caramelize sugar you transform the white sweet crystals of sucrose molecules into a brown less sweet and flavourful complex mixtures of all sorts and sizes of molecules.
You caramelize sugar by heating it to high temperatures, well above 100C. At this temperature sugar will be liquid and chemical reactions start occurring that develop the flavour & colour of a caramel. In order to get to this stage you can heat either dry sugar in a pan and heat it (but this can be trickier since it is more prone to local burning & crystallization) or you dissolve sugar in water first. The second method is easier and will give the exact same result as the other one, it’s the method we use in this Torta and in our caramel nut tart.
The most tricky aspect of making a simple sugar caramel is that it may crystallize. Sugar has a high tendency to crystallize whenever it can. Some left over crystals on a spoon or the side of a pan can induce crystallization. Luckily, we’ve written about fixing a caramel before. All you need to do is add some water to the crystallized sugar and restart the heating and evaporation process (read the other post for more details).
Whereas making caramel is pure chemistry, grinding nuts is mostly physics. As we mentioned when discussing roasting, nuts contain a lot of fat. When you grind down nuts (either using a food processor or a mortar & pestle) the cellular structure breaks down and this fat is released. As a result, you can transform a solid nut in a smooth paste without adding anything else. It is very similar to the way peanut butter is made.
Making (creme) anglaise
Creme anglaise is a liquid type of custard, you can still pour it. It is creamy and rich and typically used as the base for ice cream or just as a sauce. In this recipe the creme anglaise forms the base of a cream. It is thickened up by adding whipped cream and stabilized by adding gelatin (the gelatin prevents it from collapsing over time).
Creme anglaise, or custard, is a thickened up cream + milk mixture with sugar for sweetness. It gets its richness and slight thickness from the egg yolks. The egg yolks are gently cooked and help make the mixture more viscous. This works because of the proteins present in the yolk, these proteins slightly unfold because of the heat and hold onto moisture in the mixture (similar to what happens in lemon bars).
The main challenge of this component is not to overheat the egg yolk (or heat it too quickly). Doing so will curdle the eggs and you’ll get a texture more resemblant of scrambled eggs.
As we mentioned in the creme anglaise, gelatin in this recipe is used to stabilize a cream. Whipped cream + creme anglaise will make a rich and airy cream. However, this mixture isn’t very stable over time. Within a few hours time it will start losing air and collapse.
This is where gelatin comes in. Gelatin is a protein mixture and is very good in making stable gels (e.g. a panna cotta). Dissolving gelatin in the mixture will help the cream firm up when it cools down and be stable for a longer period of time. As a replacements you could use agar agar although the texture will be slightly different.
Layer 2, 3 & 5 - Hazelnut paste (you need this for the cream & crunch)
- 130g hazelnuts (best without the skins, but it works well with as well)
- 25g water
- 85g sugar
Layer 2 - Hazelnut crunch
- 35g dark chocolate
- 15g butter
- 40g hazelnut paste
- 20g corn flakes (for some crunch!)
- 115g all purpose flour
- 25g cocoa powder
- 1/8 tsp baking powder
- 1/8 tsp baking soda
- 3 eggs
- 150g sugar
Layer 1 & 4 - Cake syrup (used to moisten the cake)
- 35g sugar
- 35g water
Layer 3 & 5 - Hazelnut cream
- 5g powdered gelatin + 15 ml cold water (or use an equivalent in sheets, 6g of leaves)
- 120g whole milk
- 120g whipping cream (high fat)
- 60g hazelnut paste (from previous recipe)
- 3 egg yolks
- 45g sugar
- 240g whipping cream (for whipping up separately)
Layer 6 - Chocolate mousse
- 100g whipping cream
- 100g dark chocolate
- 250g whipping cream (for whipping separately)
Layer 7 - Mirror glaze (we have more information on mirror glazes)
- 7g powdered gelatin + 15g water to pre-soak
- 85g water
- 80g cream
- 40g cocoa powder
- 120g sugar
You can make this a few days in advance if you want. Just store it in an airtight container until you need it.
- Roast the hazelnuts in a preheated oven at 180C (=350F) for about 15 minutes. Check on them regularly (every 5 minutes) and remove them from the oven when they're a nice light brown and clear smell like hazelnuts. Leave to cool
- Add the water and sugar to a pan. Bring the water to the boil and ensure all the sugar has dissolved once it is boiling. Leave to cook until it starts to caramelizing. Once it has turned a light brown, add in the hazelnuts and pour onto a heat resistant surface covered with parchment paper (caramelized sugar is very hot, about 160C (=325F)!
- Leave to cool down, the caramel will harden up.
- Once it has cooled down and turned solid (it should not be flexible, that will make it hard to break up), place in a food processor and grind down until you've got a paste.
You can make this well in advance, a few hours or even a day won't matter.
- Melt the butter and chocolate in a micro wave proof bowl in the microwave by heating it on moderate for 30s at a second, stirring in between. If you leave it in too long it might burn.
- Mix in the other ingredients (hazelnut paste & corn flakes) and set aside until you need it for assembly.
On the day itself it is best to start with the cake (even if you haven't yet prepared the hazelnut paste and crunch). The cake needs to cool down fully before you can start asssembling).
- Mix the flour, cocoa, baking powder & soda together.
- Add the eggs and sugar to the bowl of a stand mixer with the whisk attached. Whisk the mixture until it becomes light and fluffy, it should foam up quite a bit. Whisk it until you're able to drop part of the mixture into itself without it sinking in immediately.
- Add half of the flour into the egg mixture and fold it in gently using a spatula. Once it is all mixed in, add the other half. You want to fold it in gently to ensure you don't lose a lot of air.
- Pour the batter into a 20cm round springform or cake tin. Bake immediately in a pre-heated oven at 190C (=375F) for about 15 minutes.
- Take the cake from the oven and leave to cool to room temperature.
- Add the sugar and water to a pan. Bring the water to the boil. Once it's boiling, take care all the sugar is dissolved and then take it from the heat. Leave to cool until assembly.
Make this within half an hour of when you actually need it. The gelatin will start setting as soon as it is done making it harder to spread out properly. The cream is made of an anglaise, mixed with whipped cream.
- Soak the gelatin powder in cold water and leave on the side until you need it.
- Add the milk, cream and hazelnut paste to a saucepan and heat until it almost boils. Take it off the heat. (You want to pre-heat the milk since you can do this quite rapidly, once the egg is in you have to be a lot more gentle to prevent cooking the egg.)
- Mix the sugar and yolks together in a bowl large enough to also hold the milk mix.
- While whisking, gently pour in about a third of the heated milk mixture. Whisk until completely mixed and then add the remainder of the milk mixture.
- Pour everything back into the saucepan and gently heat up to 82C (160F), while continuously whisking. You will notice that the mixture thickens up slightly, but it is hardly visible so using a thermometer will definitely help here!
- Take the mixture from the heat and add in the gelatin. It will dissolve quite easily now.
- Leave to cool until it's room temperature. Do not do the next step any sooner or your whipped cream will collapse since it can't handle heat well.
- Whip up the second portion of whipping cream and whip until you have firm peaks. That is, the whipped cream will hold its shape well.
- Add a third of the whipped cream to the milk mixture, fold in until you see no more lumps of whipping cream. Now add the rest in the same manner, one third at a time.
Prepare this after the cream and just before you need it in assembly. You can start assembling the cake before you start the chocolate mousse.
- Break the chocolate in pieces and place in a microwave proof bowl. Melt the chocolate in several sessions of 30-60s in the microwave at a medium power. It depends a lot on your microwave how fast this goes. Stir in between to prevent burning.
- Stir in the first portion of cream. If your cream is col you may want to re-heat it in your microwave, but only for a short amount of time. When mixing in the cream it may seem like it seizes, but don't worry, just continue stirring and it will all come together well. It will become a dark brown, thick and rich mixture.
- Leave to cool until it is at room temperature. It is now best to wait with the next steps until you are almost ready to use the mousse on the cake.
- Whip the second portion of cream until it creates stiff peaks.
- Fold in the whipped cream into the ganache in a similar way as you did for the cream. That is, mix it in in three different portions. This way you lose as little as air as possible.
- Once your mousse is ready it will start thickening, therefore, do not prepare this too soon.
Prepare this right at the moment that you need it. Do not prepare in advance since the gelatin will start setting and will make it impossible to use nicely. We have a more extensive guide here.
- Pre-soak the gelatin in the specified amount of water.
- Add all the other ingredients to a pan and bring to the boil. Once it is boiling, take it off the heat and add the pre-soaked gelatin. Stir until it is dissolved, which should go very rapidly.
- Leave the mirror glaze to cool. You want to pour it over the cake when it is in between 32-37C (90-100F). It should be liquid enough to pour, but viscous enough to not flow off completely again.
Layer 1: Take your cooled down cake and cut it down horizontally so you end up with two thin cakes. If your top is very domed (we're using very little leavening agents to prevent just that) you might want to straighten it a little bit, but it doesn't have to be perfect. Take the bottom half of the cake, place it back in the spring form. Take half of the cake syrup you made and spread it over the cake.
Layer 2: Take the praline crunch and spread out over the cake. If it got too solid, give it a slight heat boost in the microwave and feel free to break it into smaller pieces. Place the cake in the fridge to set.
Layer 3: Take half of the freshly made Bavarian cream and spread it in an even layer over the cake. Place it back in the fridge and leave it until it is slightly firm and strong enough to hold a next layer without collapsing. (Do not store the 2nd half of cream in the fridge, it will thicken too much.)
Layer 4: place the second layer of cake on top of the cake and coat with the remainder of your syrup, try to spread the syrup evenly that all parts are soaked similarly.
Layer 5: Spread the remainder of the cream on top, again, try to get the top as straight as possible. Leave to firm up in the fridge again. You want it cooled down properly after this step, that will help the chocolate mousse to set properly.
Layer 6: You now have to cover the whole cake in the chocolate mousse. Try to get the thickness of the sides and the top as evenly as possible. Also, make the whole cake as smooth as possible. The mirror glaze can't really hide any defects, so you will continue to see major defects through the glaze. Leave to set in the fridge and wait for the mousse to fully set.
Layer 7: Pour the mirror glaze over the cake. As described in the section on mirror glaze, you want to cool down the mirror glaze to approx. body temperature for the best results.
Kitchen detail, Juicy Post: Setteveli – The Ne Plus Ultra Of Sicilian Cakes, 2018, link
Unfortunately I do not read Italian, that would have been the best way to learn about. But I did my best (thanks Google Translate). Despite not being able to read everything these website did shine a good light on the cake and its name:
A very similar looking cake (but different name) is sold at other patisseries, link
Torta Setteveli, website of the original cake
La farfalla di cioccolato, Torta, Settestrati, 2010, link
Dolcemente salato, torta setteveli, anzi settestrati, 2012, link