01 -
Mix up your vanilla cake following the directions on the box and bake it in a well-greased 9x13 inch pan. Once it's done baking, let it sit and cool down for about 25 minutes - you want it cool but not completely cold.
02 -
Take a drinking straw or the handle end of a wooden spoon and carefully poke holes all across the top of your cake. Make them evenly spaced and go deep enough to create good pockets for the gelatin.
03 -
Make each gelatin flavor separately using 1 cup of boiling water mixed with only 1/2 cup of cold water per box. This creates a slightly thicker consistency that won't make your cake soggy.
04 -
Working with one color at a time, slowly pour or spoon the blue gelatin over roughly half of your cake, making sure it seeps down into all those holes. Then do the same with the red gelatin on the other half.
05 -
Cover your cake and refrigerate it for at least 6 hours, though overnight is even better. This gives the gelatin time to fully set inside the cake and creates those beautiful color pockets.
06 -
Spread the thawed whipped topping evenly across the entire surface of your cake. Sprinkle on your patriotic decorations, slice into generous squares, and watch everyone's faces light up when they see those amazing colors!