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It’s the cream of a pastry chef: creme patissiere, or creme pat in short. A fancy version of cream. It’s thick and creamy, and works well in a range of treats – what about filling some choux pastry with creme pat? Luckily, despite being a pastry chef’s cream, it’s not hard to make. On the contrary, once you know a few tips and tricks, it’s done in no time!
What is creme patissiere?
Creme patissiere, creme pat, or pastry cream, is a French delicacy. In French you’d write crème pâtissière, loosely translated as ‘cream of a pastry chef’. It’s not made with cream though. Instead, it’s thickened milk, with some added sugar for sweetness. You thicken the milk using flour and eggs, making it a sturdy version of a custard.
You’d generally use creme patissiere in cool or room temperature applications. You’d find it as a filling in choux pastry, or at the bottom of a fruit tart.
Eggs & flour thicken creme pat
So how come a creme patissiere is so nice and thick?
It’s all about balancing the effect of eggs and wheat flour. Both can thicken milk, but, when you use them together you have the benefits of both. Let’s have a look at eggs first.
Egg yolks thicken with proteins
You don’t use whole eggs to make creme pat, you just use the yolks, just like you do for a creme brulee for instance. The functional ingredients in egg yolks for pastry cream are fats, proteins, and lecithin. Fats help make the pastry cream creamy and rich. The lecithin helps to mix the water and fat, to create a smooth homogeneous texture. But it’s the proteins that thicken.
When egg yolk proteins are heated their properties change. They uncurl and take on a new shape that is better at holding onto water. By holding onto water, the overall mixture thickens.
Making egg-free creme patissiere?
You can make creme patissiere, or at least something that looks very much like it, without eggs. Instead of eggs, you could use corn starch, just like making eggless custard ice cream. Keep in mind that the texture will be different. It might be a little thicker, and less creamy and rich. You could overcome this by adding a little cream (which contains a lot of fat).
When replacing eggs, start by replacing 1 egg yolk with 2 tsp of corn starch.
Flour thickens with starch
Flour on the other hand barely contains any fat. Instead, flour contains a lot of carbohydrates, more specifically: starches. Starches are very good at thickening liquids. When you heat starches mixed with water they gelatinize. That is, the starches absorb a lot of water and release a lot of those water absorbing molecules that all hold onto water.
Since flour doesn’t contain fats, liquids thickened with flour are less rich and creamy. But, flour is a very effective thickener. You need less flour than egg yolk to reach the same thickness.
Instead of using flour, you may find that some recipes will use some sort of starch, such as potato or corn starch. This works in a very similar way. The starches will also thicken the mixture.
You can decide to substitute both the flour and the egg with corn starch. However, the texture of the creme pat will be different. It’s still a custard, and it’s still thick though, so feel free to experiment!
How to make creme pat
Making creme patissiere, or pastry cream, takes just a few steps. It’s not complicated, but it is important that you do things in the right order, or you’d end up with a lumpy version.
Remember that making pastry cream is all about thickening the milk. Both the egg yolks and the flour can thicken. However, both should be handled carefully. Egg yolks may scramble, or curdle. Flour can form lumps. So making a creme pat is all about ensuring they can thicken the milk, without showing these undesirable side effects!
Let’s have a look at how to do so.
Step 1: Mix egg, sugar and flour
The best way to prevent lumping of flour is to mix it with a cold liquid. When that liquid is still cold, the flour won’t gelatinize yet. As such, you can easily mix it in. If you mix flour with a hot liquid though, the outside of flour particles will gelatinize very quickly. As a result, the particles don’t have time to mix properly. The dry inside will be trapped within the thickened gelatinized layer.
When making pastry cream, mix the egg yolks and sugar first. This loosens up the egg and makes it easier to then mix in the flour as well. It should be easy to make a smooth batter!
Step 2: Heat milk
Egg yolks are prone to overcooking. As such, you’d want to heat them gently. However, that can take a long time.
So, what you do instead, is heat up the milk. You can heat up milk quite rapidly, without any challenges – just be sure it doesn’t boil over! Once it’s hot, you can use it to ‘temper’ the eggs. That is, you pour the hot milk into the egg mix. That way, the eggs + flour + sugar mixture starts to heat, without overcooking.
It’s important that you mix the eggs, while adding the hot milk. You don’t want any local hot spots that could overcook the eggs. Egg yolks start to cook at about 60-70°C. As long as you continue whisking while adding the milk, the final temperature of the mix will remain lower than the temperature at which they cook.
Step 2b (optional): Add flavor
Some recipes also use this step to infuse flavor. Add in a vanilla bean, some ground coffee, or spices and let them sit in the warm milk for some time. The flavor molecules from these ingredients will slowly seep into the milk. This happens a lot faster in hot milk, than it does in cold!
Just before you’d use the milk, just sieve out the added ingredients and quickly re-heat the milk before pouring it onto the eggs.
Step 3: ‘Cook’ the egg + milk mix
Last, but not least, it’s time to actually put the flour and egg yolks to work!
It’s time to continue heating the warm mixture of egg, sugar, flour, and milk. Since the mix is already warm, this final step won’t take long. But, it is important that it’s stirred continuously. Thickening will happen quite rapidly and if you don’t stir, you’ll still end up with clumps of pastry cream that have thickened too fast.
When determining whether your creme patissiere is done, keep in mind that it will thicken when it cools down! The starches in the flour especially will continue to absorb some water. And, at lower temperatures, the molecules in the creme pat just aren’t as mobile anymore, causing it to thicken further.
Step 3b (optional): Add flavor
There’s another opportunity to add flavor to your creme patissiere, right at the end. Creme pat is quite a resilient product. It can handle quite a lot of additions. For instance, you could add flavor extracts, or some cocoa powders. You could even add some fruit jams or pastes. Just keep in mind that anything with a lot of water will change the consistency of the pastry cream, making it thinner.
Once your creme patissiere has cooled down, it’s ready to use! How about using it to fill choux pastry, in a fruit tart, or as a donut filling? Or, how about trying to make your own? You have all the knowledge you should need now! Try varying the ratios of milk, sugar, eggs, and flour to make your optimal pastry cream. There’s no one perfect recipe. Everyone will prefer something slightly different.