Vanilla pastry cream is a basic recipe that you should master. It's great for serving with crêpes for breakfast but also as a filling for tarts, cakes, and éclairs!
Heat the milk on medium–high heat in a medium saucepan with half of the sugar and the split vanilla beans (seeds scraped into the pot).
Meanwhile, beat the egg yolks with the remaining sugar in a medium bowl until the mixture has lightened in color, then add in the flour and starch, and whisk again to combine. Scrape down the sides of the bowl. The mixture should be smooth.
When the milk is hot and almost boiling, pour the hot milk over the egg mixture, whisking continuously until the mixture is homogeneous. Transfer the mixture back to the saucepan and continue heating it, whisking constantly until the mixture has thickened and boiled for about 3 minutes.
Take the mixture off the heat. Transfer to a plastic-wrap lined rimmed sheet (or a bowl over an ice bath). Spread out the pastry cream evenly over the entire plastic wrap-covered surface. Top with another piece of plastic wrap to seal it, making sure the plastic wrap is in direct contact with the filling. Transfer the pan to the fridge and let cool completely, at least 3 hours or overnight.
When you are ready to use it, transfer the pastry cream to a bowl and re-whip it with a whisk to smooth it out and loosen it so that you can spread it or pipe it.
Notes
Make sure to read through the entire blog post and recipe, including the notes before proceeding so that you are familiar with the steps and what each ingredient in the recipe does.
Remember to make pastry cream ahead of time because it has to cool, depending on what you plan to do with it. You can use flour, cornstarch, or a combination of both to make pastry cream. Which thickener you use is dependent on what you plan to do with the filling.
For a tart that you want to slice cleanly, the filling must hold its shape, so you will use more cornstarch and less flour.
For a crêpe filling, the pastry cream can be looser, and so you will only use flour.
Pastry cream must come up to a boil and boil for several minutes, not only to thicken it, but also to make it safe to consume as it is made with flour and eggs, which need to be cooked.
Strain the pastry cream to remove lumps and make sure it is creamy and smooth.
Always cover pastry cream with plastic wrap in direct contact to avoid it drying out or forming a skin on the surface.