I made a cake several years back with the same theme. The difference between mine and that cake was that I piped whipped cream between the rows of strawberries, which were cut into rectangles, and placed directly on the cake. The blue berry field was identicle, but with whipped cream piped into stars. It wasn't accurate in numbers of stars, but it looked and tasted great. The cake I used was angel food cake, and the whipped cream was stabilized with gelatin. This is an easy cake to do.
I've also made a red, white (off-white), and blue cheesecake, with each layer a separate color. This was trickier. I blind baked the crust after making 3 separate layers of cheesecake filling. To make the layers, simply line the spring-form pan with parchment paper, pour in the cheescake filling, and bake until firm set. When cooled, remove the pan sides, and slide a thin, plastic cutting sheet between the firm custard and parchment paper. Set aside and repeat for each colored layer.
To color the layers, I added food coloring, and pie filling to the layers. The white layer was the filling for a New York Cheesecake.
The custard will have shrunk in diameter just a little.
Blind bake a graham cracker crust in the same spring-form pan. When it is done, and chilled, gently lift each layer of filling, and slide it from the cutting sheet, into the crust. Top with decorative swirls of blueberry, and strawberry pie filling, or glaze, or freezer jam. It was so good, and no one could figure out how I made it.
Seeeeeeya; Chief Longwind of the North