Step 1

Place 1 1/2 cups milk and the vanilla into a medium saucepan. Cook over high heat, stirring often until it just starts to simmer. Remove from heat.

Step 2

In a medium bowl, whisk remaining 1/2 cup milk, egg yolks, sugar, and cornstarch.

Step 3

While whisking vigorously, slowly pour the hot milk into the egg mixture.

Step 4

Return mixture to saucepan and cook over high heat, whisking constantly, until it thickens and comes to a boil.

Step 5

Pass through a strainer and into a bowl. Place plastic wrap directly on top of the custard to prevent a skin from forming.

Step 6

Cool to room temperature then place in the refrigerator for a couple hours to set.

Step 7

Store in an airtight container in the fridge for up to a week. Do not freeze.

Step 8

Ensure pastry cream and butter are at room temperature. Whip pastry cream by hand until smooth.

Step 9

Using a stand mixer or hand mixer, beat the butter on high until pale and fluffy (3 mins). Add the room temperature custard 1 Tbsp at a time, incorporating well after each addition. Add powdered sugar or more vanilla if desired. Beat for 2-3mins until smooth and fluffy.

Step 10

Store in an airtight container in the fridge for up to 2 weeks or freeze for up to 3 months. Allow buttercream to come to room temperature and rewhip before use.