Cupcakes:
2 sticks (1 cup) unsalted butter, softened
1 3/4 cup granulated sugar
4 large eggs
1 cup whole milk
1 tablespoon pure vanilla extract
1/2 vanilla bean, seeds scraped out
2 3/4 cup all-purpose flour
1 1/2 teaspoon baking powder
1/2 teaspoon salt

Chocolate Buttercream:
1 1/2 sticks (3/4 cup) unsalted butter, softened
1/2 cup unsweetened cocoa powder
1/2 teaspoon salt
2 1/4 cup powdered sugar, sifted
1 teaspoon pure vanilla extract
2 tablespoons milk
1/2 cup heavy cream
1/3 cup Ovaltine