Another Yellow Birthday Cake with Chocolate Frosting

INGREDIENTS

For the Cake:

1 cup

butter, melted

1 3/4 cups

sugar

2 tsp

vanilla

large eggs, room temperature

large egg yolks, room temperature

2 cups

all purpose flour

1/4 cup

cornstarch

1 1/2 tsp

baking powder

1/4 tsp

baking soda

1/2 tsp

salt

1/2 cup

milk (1% or above), room temperature

1/2 cup

sour cream (regular), room temperature

For the Buttercream:

3 sticks

(1-1/2 cups) butter, softened to room temperature

5 cups

powdered sugar

3/4 cup

cocoa powder

5 tbsp

milk or cream

2 tsp

vanilla

1/8 tsp

salt