Black Out Cake from the Fifties Recipe

Ingredients

1/3 cup unsweetened cocoa powder
1 cup milk
2 1/4 cups cake flour
1 teaspoon baking powder
1 teaspoon baking soda
1/2 teaspoon salt
1/2 cup unsalted butter
1/4 cup shortening
2 cups white sugar
3 eggs
2 teaspoons vanilla extract