Yellow Butter Cake with Chocolate Frosting

INGREDIENTS

For the cake:

2 sticks

unsalted butter, at room temperature, plus more for greasing pans

1 1/2 cups

all-purpose flour, plus more for dusting pans

1 1/2 cups

cake flour

1 tbsp

baking powder

1/2 tsp

salt

1 3/4 cups

sugar

large eggs

2 tsp

vanilla extract

1 1/4 cups

milk

For the frosting:

1 lb

semisweet chocolate, finely chopped

6 tbsp

Dutch-process cocoa powder

6 tbsp

boiling water

3 sticks

unsalted butter, at room temperature

1/2 cup

confectioners’ sugar, sifted

salt