How do I make Chocolate Rainbow Surprise 'Box' Cake?
Here's a recipe for Chocolate Rainbow Surprise 'Box' Cake:

Ingredients:

• 1 box chocolate cake mix, plus corresponding ingredients - eggs, oil, water
• 1 box white cake mix, plus corresponding ingredients - eggs, oil, water
• food coloring
• 16 oz cake frosting

Instructions:

1. Prepare Chocolate and White Cake Mixes according to directions on the box.
2. NOTE: It is recommended that you use the same brand of cake mix for each, and ensure they share a similar bake time.
3. Divide prepared White Cake Batter into 4 separate bowls. Use food coloring to create vivid Red, Yellow, Green, and Blue Batter.
4. In a greased bundt pan, spoon about 1/3 of the prepared Chocolate Cake Mix onto the bottom. Using a tablespoon, carefully spoon a thin ring of Red Cake Batter on top of the chocolate layer - being careful to keep it centered and ensure it does not spread to the edge of the pan.
5. Repeat with Yellow, Green, and Blue Batter, carefully spooning each on top of the previous. Finish by carefully covering the colored layers with an additional 1/3 of the Chocolate Cake Mix (leaving about 1/3 extra so as not to overfill the pan).
6. Bake in a preheated oven for 35 minutes at 350°F (175°C). Remove from oven and allow cake to cool.
7. Turn out onto a plate and decorate.

Enjoy your Chocolate Rainbow Surprise 'Box' Cake!