adapted from Barefoot Contessa Family Style by Ina Garten
18 Tablespoons butter at room temperature
2 1/2 cups sugar (I reduced this from the 3 she listed)
6 eggs
1 cup sour cream
1 1/2 t vanilla
3 cups all-purpose flour
1/3 cup cornstarch
1 t salt
1 t baking soda
Heat oven to 350 degrees. Spray a full sheet pan with cooking spray. Cream the butter and sugar in your mixer with a paddle attachment on high speed. On medium speed, add the eggs one at a time and then the sour cream. Sift the dry ingedients together and add them on low speed. Mix until just incorporated. Spread into prepared pan and bake 20-30 minutes or until toothpick comes out of center clean.
Frosting
4 sticks butter, room temperature
1 1/2 lbs. cream cheese
1 lb confectioners' sugar, plus more
1 1/2 t vanilla
Mix all ingredients with an electric mixer until smooth and creamy. Add additional powdered sugar if frosting seems too thin.
Spread a thin layer of frosting over the entire cake. Then use a toothpick to draw a flag design on the cake. Place blueberries in the top corner and then place two rows of raspberries near the top. Pipe two rows of icing, using a large star tip. Repeat for remaining cake. Pipe stars on top of blueberries to finish off the cake.