In a mixing bowl, combine water, eggs, and sponge mix. Mix on low speed for 1 minute.
Scrape down the sides of the bowl, then increase the speed to high and whisk for 5 minutes until the batter is smooth and airy.
Divide the batter into separate bowls, depending on how many colors you want to use.
Add a few drops of food coloring to each bowl and mix until fully incorporated.
Transfer the colored batter into a cake tin and bake.
While the cake is baking, store the remaining colored mixtures in the fridge.
Bake in a preheated oven at 180°C for 10 minutes, or until a skewer inserted into the center comes out clean.
Allow the cakes to cool completely.
Once all cakes have cooled, layer them with a generous amount of butter icing between each layer. Cover the entire cake in butter icing and decorate as desired.
Enjoy a light, fluffy classic sponge cake, perfect for any occasion!
