- 25 Minutes
- 30 Minutes (plus cooling time)
- For the cake, preheat the oven to 350°F and grease a 9x13 inch baking pan with nonstick cooking spray.
- Whisk the cake mix, water, oil and eggs together in a large bowl until smooth.
- Spread the batter evenly into the prepared pan. Bake until a toothpick inserted into the center comes out clean, about 25-30 minutes. Poke the cake with the end of a wooden spoon in 1-inch intervals. Cool in the pan completely before frosting, about 1 hour.
- For the assembly, fold the frosting, 3 cups of the whipped topping and food coloring together in a large bowl until smooth. Combine the remaining whipped topping and marshmallows in a medium bowl. Spread the green frosting mixture evenly over the cooled cake. Place each color of the rainbow candy or cereal on top of the cake in the shape of a rainbow. Spoon the marshmallow mixture on the bottom of each end of the rainbow. Arrange your favorite chocolates on the marshmallow mixture and decoratively on top of the cake. Pipe shamrocks on the cake with the remaining green frosting mixture. Keep refrigerated until ready to serve.
Recipe Tip: Pick up a 2 liter MTN DEW® soda from your local Food Lion for a cheers-worthy St. Patty’s Day celebration!