For maximum popping potential, pour the Pop Rocks into the cake centers no earlier than 1 hour before serving. The moisture in the cakes will cause the Pop Rocks to slightly snap and crackle on their own. In fact, they make a great sizzling sound on the plate. After about 4 hours, the Pop Rocks lose most of their popping power, so plan accordingly.
- 1 box white cake mix, like Duncan Hines 
- 1/4 cup vegetable oil
- 3 large egg whites
- Red and blue food coloring
- Simple syrup , for dipping
- Red, white, and blue sanding sugar, for decorating
- 1/4 cup vanilla buttercream frosting
- 3 packages Pop Rocks candy 
- Black licorice ropes , cut into 1-1/2-inch long pieces
- To make cakes: Preheat oven to 350°F and coat 3 quarter sheet pans  with cooking spray and lightly flour the bottoms.
- Follow white cake box instructions to make cake batter. Pour 1/3 of the white cake batter into 1 of the prepared pans. Pour another 1/3 into a separate bowl. Mix in several drops of red dye to one bowl until a red cake batter forms, and repeat the process with the blue dye and the other bowl of batter. Transfer each to the remaining pans.
- Bake the red, white, and blue cakes according to the package directions, or until a toothpick test comes out clean. Allow them to cool 5 minutes before flipping the cakes onto a wire rack to cool completely. Using a 1-1/2-inch round cookie-cutter, cut circles from each of the baked cakes. With a serrated knife, carefully trim off the browned, baked bottoms of each cake circle.
- To assemble: Lightly roll the outer ring of each cake in simple syrup, then roll in the corresponding sanding sugar color (i.e.: roll the blue cake in blue sanding sugar). Using a jumbo straw (a bubble tea straw  will work), punch out the centers of the cake circles. Save the red and blue centers to use as plugs for later. Using a serrated knife, carefully split both the red and blue cake plugs into 2 thinner plugs. Insert the blue cake plugs into the bottoms of the blue cake circles. Pipe a line of frosting around the tops of the blue cake circles and stack the white cake circles on top, firmly pressing down to glue the 2 together. Repeat this process to glue the red cake circles to the white cake circles.
- Fill the hollow centers of the stacked cakes with Pop Rocks, leaving 1/4 inch of headspace at the top. Seal the top of each cake with a red cake plug. Insert licorice rope into the center of each cake. Serve immediately!
- Desserts, Cake
- North American
- 10 to 14 small cakes