Preheat your oven to 350°F (175°C).

In a large mixing bowl, combine the vanilla cake mix, water, vegetable oil, and eggs. Mix until well combined.

Pour the batter into two 9-inch round cake pans, evenly distributing the mixture.

Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

Once baked, allow the cakes to cool in the pans for 10 minutes, then transfer them to a wire rack to cool completely.

While the cakes are cooling, prepare the frosting. Divide the can of white frosting into three bowls.

In the first bowl, add red food coloring to create red frosting. In the second bowl, add blue food coloring for blue frosting. Leave the third bowl white for the base.

Once the cakes are completely cool, place one layer on a serving platter. Spread a layer of white frosting on top.

Carefully place the second cake layer on top and frost the entire cake with the remaining white frosting.

Use the red frosting to create stripes on the left side of the cake, and use the blue frosting to create a square at the top left corner.

Decorate the blue frosting area with star-shaped sprinkles to resemble stars.

Arrange the sliced strawberries in the red stripe area and place the blueberries in the blue square area to complete the flag design.

Slice and serve your Flag Cupcake Cake, perfect for any festive occasion!