Creme Mousseline Recipe

Pastry cream

1. In a medium-sized saucepan, place the milk and salt, and heat until it’s just about to simmer (or just simmering). The milk does not need to come to a boil.
2. While the milk is heating, in a separate bowl or jug, place the egg yolks, sugar, vanilla, and cornstarch. Whisk very well until the egg yolks start to look a little pale in color and thick, and there are absolutely no lumps in the mixture. Scrape the sides and bottom with a spatula and whisk again to make sure there are no yolk lumps.
3. When the milk is hot, turn off the stove and remove the milk from the heat.
4. Temper the egg mixture by pouring the hot milk into the egg yolk mixture in a SLOW and THIN stream while constantly whisking the egg yolk mixture. This will ensure that the egg mixture gently warms up without turning into scrambled eggs. You'll only need to add about 1 cup of the milk mixture to temper the eggs.
5. Once the egg mixture is tempered, add the tempered egg mix back into the pot with the rest of the milk, and return it back to the stove.
6. Heat the custard base over medium heat (or medium-low if you're a beginner) while whisking very frequently. Make sure to use the whisk to scrape the sides, bottom and corners of the pot to ensure that the milk is not “setting” anywhere and forming scrambled eggs.
7. The custard will start to thicken. Keep whisking until the custard starts to come to a boil. To check if the custard is boiling, you will need to pause whisking for a few seconds at a time to check if there are any bubbles breaking the surface.
8. When the first few bubbles start to break the surface, keep cooking the custard while constantly whisking very well for at least another minute (up to 90 seconds).
9. When the custard has finished cooking, remove it from the heat and add half of the butter (175 g / 12 tbsp). Use only (150 g / 10.5 tbsp) if adding praline paste.
10. Whisk the butter to melt it into the custard and mix it in.
11. Once all the butter is mixed into the custard, pass the custard through a sieve into a bowl or container to remove any lumps.
12. Place a plastic wrap over the surface of the custard, making sure that the plastic wrap is touching the whole surface of the custard to prevent a skin from forming on top.
13. Chill the custard for a few hours or overnight until cold. You can let it cool to room temperature and use it immediately as well.

Creme mousseline

Preparing the butter

1. If you prefer a fluffy, airy creme mousseline, you can use pastry cream straight out of the fridge. For a creamy, slightly more dense, smooth mousseline cream, let the pastry cream come to room temperature. You can either use the pastry cream as soon as it cools to room temperature (around 70 F), or allow the chilled pastry cream to come to room temperature for a couple of hours.
2. Place the remaining softened butter (175 g / 12 tbsp) in a mixing bowl. Use only (150 g / 10.5 tbsp) if adding praline paste.
3. With a whisk attachment or paddle attachment in your stand mixer (or hand-held mixer), whisk the butter until it's creamy and has absolutely no lumps. For a fluffy result, whisk the butter with the whisk attachment until it look airy and fluffy. For a more creamy, smooth texture, use a paddle attachment.
4. Add the praline paste (if using) and mix it in to the butter mixture. Use a whisk attachment for fluffy and airy results, or use a paddle attachment OR a spatula to prevent air incorporation.

Adding the pastry cream

1. Add the custard into the butter in spoonfuls while mixing the butter mixture, until all of the custard has been added. Use a whisk attachment to get a buttercream-like texture. Or use a paddle attachment to add less air.
2. Scrape down the sides of the bowl periodically while mixing to ensure that all the butter and custard are evenly mixed.
3. Whisk until you have a smooth, creamy, pipeable mousseline cream.
4. If the mixture is too runny, or warms up too much, or it’s very warm in your kitchen - transfer the mousseline bowl into the fridge and let it cool down. Then re-whisk it to get a firmer, pipeable cream. Chilling the cream longer and re-whisking it well can give you a fluffier texture.
5. You can achieve your preferred cream texture by altering how long you whip the butter and the final cream. Please see recipe notes.
6. Use the mousseline cream immediately, or within 1-2 days for best results.