We didn’t quite manage to get these done for the Fourth, but decided to make them anyway. The base is plain sugar cookie dough we made yesterday. I dyed 1/4 blue and dived the remainder into two parts, dying one part red. The dough is really soft so we wrapped it in plastic wrap and refrigerated it until today.
With the assistance of waxed paper I formed the blue dough into a tube and then squared it off.
The red and the white were rolled out (separately) between layers of waxed paper into a more or less rectangular shape. With some trimming and piecing we got this to work. I don’t have any exact measurements for the strips, but eye-balled it into this:
Of course, if you really want to get it right, you can use this cutting board from Signals.