American Flag Sponge Cake

Ingredients

• 2 1/4 sticks Unsalted butter
• 3 cups Sugar
• 6 Eggs
• 1 cup Sour cream
• 1 1/2 tsp. Vanilla Extract
• 3 cups All-Purpose flour
• 1/3 cup Cornstarch
• 1 tsp. Salt
• 1 tsp. Baking soda
• 1 1/2 Ibs. Cream cheese
• 4 sticks Unsalted butter
• 1 Ib. Powdered sugar
• 1 pint Blueberries
• 2 1/2 pints Raspberries