Rainbow cake with colored icing

Ingredients:

• 1 package (517 g) of dry mix for making white sponge cake (see recipe for white sponge cake). Here)
• 1 and 1/4 cups of water
• 1/3 cup vegetable oil
• 3 egg whites
• 0.5 tsp vanilla extract
• 1 tbsp each of dry jelly flavors: lemon, orange, cherry, grape, lime, and blue raspberry
• 2 cups of boiling water
• 2 jars of 340 g. white whipped cake icing
• Colored decorative glaze: yellow, orange, red, purple, blue, green

Preparation:

1. Preheat oven to 350°F (175°C). Spray 2 8-inch (20cm) cake pans with cooking spray.
2. In a large bowl, beat the cake mix, water, vegetable oil, egg whites, and vanilla with a mixer on low speed for 30 seconds. Use a spatula to scrape down the sides of the bowl and beat on medium speed for 2 minutes.
3. Pour the batter evenly into the prepared pans and bake for 32-36 minutes, or until a toothpick inserted into the center of the cake comes out clean. Using oven mitts, remove the pans from the oven and let the cakes cool for 10-15 minutes before turning them out onto a wire rack to cool completely. Trim the tops of the cakes to create a smooth surface.
4. Place 1 tablespoon of each dry jelly into small bowls. Add 1/3 cup of boiling water to each bowl and stir until the gelatin is completely dissolved. Sprinkle the cut sides of the cakes with the different types of jelly, covering the entire surface. Wrap the cakes individually in plastic wrap and refrigerate for 3-4 hours.
5. Remove the cake layers from the refrigerator and unwrap them. Place one cake layer on a plate or stand and spread white frosting evenly over it. Place the second cake layer on top and frost the entire cake, top and sides, with the remaining white frosting. Spread large spoonfuls of frosting in different colors randomly over the entire surface of the cake. Use a small offset spatula to create swirls in the frosting to create a rainbow or tie-dye effect.