Homemade Confetti Cake with Vanilla Buttercream Frosting

For the vanilla confetti cake:

all-purpose flour

baking powder

baking soda

kosher salt

unsalted butter, softened

granulated sugar

large eggs

egg yolks

vanilla bean paste or vanilla extract

buttermilk

rainbow jimmies sprinkles* (NOTE: nonpareils sprinkles will bleed so I do not recommend for the cake batter - however, you can use for decorating the outside of the cake)

For the Vanilla Buttercream Frosting:

unsalted butter, softened

cream cheese, softened

confectioners’ sugar

heavy cream

vanilla bean paste

salt