Place the butter and sugar in a bowl and beat with an electric mixer until pale and fluffy. Add the vanilla extract and eggs one at a time, mixing with each addition.

In a separate bowl, mix together the flour, baking soda and salt. Add this to the butter mixture in 2 additions, alternating with sour cream.

Grease and flour four 9-inch round cake pans. Pour ¼ of the batter into one pan and set aside. Place 1/3 of the remaining batter into a bowl and dye it blue. Pour it into another cake pan. Dye the remaining batter red and divide between the 2 remaining cake pans. and bake at 350F for 25-30 minutes, or until a skewer inserted into the cakes comes out clean.

Cool the cakes in the pan for 5 minutes, then transfer to a wire rack and cool completely.

Beat the butter with an electric mixer until pale and fluffy. Add the vanilla extract and beat until combined. Add the confectioner’s sugar one cup at a time, then beat for 3-5 minutes, or until fluffy.

Slice the tops off, bottoms and sides off all cakes to flatten them and remove any browning. This will make the cake look cleaner when sliced.

Slice the red and white cakes into 2 layers. Leave the blue cake as one layer. Gently stack one red and one white layer on top of the blue cake. Use a 4-inch round cookie cutter to cut a circle into the center of all the cakes. Then gently separate the layers. Reserve the red and white center and the blue outer ring. Use the red and white rings and the blue center for other use (or nibbling!).

Place a red layer (without a hole) on a serving dish of your choice and spread some buttercream on top. Place a white layer (without a hole) on top and top with more buttercream. Repeat with another red layer and more buttercream. Place the blue outer ring on top and spread buttercream onto the top and inner sides. Insert a white center in the middle, top with buttercream, then place a red center on top.

Coat the cake in another fluffier layer of buttercream and top with some red, white and blue sprinkles.

Slice to reveal the American flag and enjoy!