Philadelphia Style Butter Cake 1 large egg 1 (18.25 ounce) box yellow cake mix 1/2 cup butter, softened 8 ounces cream cheese, softened 1 pound confectioners' sugar, sifted 2 large eggs 1 teaspoon vanilla extract Preheat oven to 350 degrees F. Grease and flour a 13 x 9-inch cake pan. Beat together the 1 egg, cake mix and butter for 5 minutes. Mix and pour into prepared pan. Cream together cream cheese, confectioners' sugar, the 2 eggs and vanilla extract. Pour this on top of the cake base. Bake for 35 to 40 minutes until browned. Cool for 15 minutes, and cut into squares.