Crème Mousseline
Pastry cream beaten with butter — firm enough to pipe
Pastry cream beaten with a great deal of soft butter until it is light and firm enough to hold its shape. This is what goes inside a fraisier or a Paris-Brest.
Both must be at the same temperature — properly room temperature, not one cold and one soft. Get that wrong and it curdles, which looks fatal and is not; see the notes.
Ingredients
- 3 cups Crème Pâtissière (see Crème Pâtissière), at room temperature
- 10 ounces (2 1/2 sticks) unsalted butter, at room temperature
- 1 teaspoon vanilla extract
Instructions
- Take both the pastry cream and the butter out of the fridge at least an hour ahead. They must feel the same temperature to your finger.
- Beat the butter in a stand mixer with the paddle until pale, light and creamy, about 5 minutes.
- Whisk the pastry cream smooth in a separate bowl.
- Add the pastry cream to the butter a large spoonful at a time, beating well after each. Add the vanilla.
- Beat for 2 to 3 minutes more, until light and glossy. Use immediately, or refrigerate and re-beat before piping.
Notes
- If it splits or looks grainy, warm the outside of the bowl briefly with a hot cloth and keep beating. It almost always comes back.
- Half the butter gives a lighter cream, sometimes called crème légère.