Prepare the white cake mix according to package instructions.

Divide the batter evenly into three bowls.

Color one bowl of batter red using red gel food coloring and another blue using blue gel food coloring. Gently stir until the color is incorporated.

Pour each colored batter into a greased and parchment-lined loaf pan.

Bake for 10-15 minutes, or until a toothpick inserted into the center comes out clean. Cool completely.

Using a 1-inch biscuit cutter, cut 8-10 circles from each cake.

Lightly brush the outside of each cake cutout with simple syrup.

Coat the brushed cake cutouts with red, white and blue sanding sugar. Allow to dry for 10 minutes.

Dab a small amount (1/4 - 1/2 tsp) of store-bought icing on each of the red cake circles.

Top the red cakes with a white cake circle. Add another dab of icing on the white cake.

Top the white cake circle with a blue cake circle.

Use a straw to cut a hole through the center of the layered cakes.

Fill the hole with popping candy.

Top each cake with a 1-inch length of black string licorice.

Serve within an hour to maintain the popping effect.