You'll need egg yolks. sugar, cornstarch, whole milk, butter, and vanilla paste.
Whisk egg yolks & sugar
Combine the egg yolks, sugar, and cornstarch in a medium bowl. Whisk for 3-5 minutes until pale in color and the mixture flows off of the whisk.
Temper & cook
Temper the egg yolks by slowly pouring in half of the simmering milk while whisking the mixture. Pour the mixture back into the saucepan and cook until thick and large bubbles form.
Add butter & vanilla
Remove the pastry cream from heat and immediately stir in the butter and vanilla bean paste.
Transfer the pastry cream to a bowl and press plastic wrap up against the surface to prevent a skin from forming. Chill overnight.
Enjoy this pastry cream on its own with fresh fruit, in my Boston Cream Whoopie Pies recipe, or turn it into german buttercream!