Preheat oven to 180C/350F/Gas 4 and spray 3 (9-inch) round cake pans with baking spray.

Using a handheld or stand mixer, place the cake mix, egg whites, water, and oil into the mixing bowl and beat to combine.

Divide the cake batter between 6 bowls. Add gel food coloring to each of the bowls so that you have one of each color - sky blue, purple, pink, yellow, green, and orange.

Scoop out a small amount of each color at a time and place it into the cake pans to create the tie dye pattern. Try not to put the same colors next to each other, and you can add on top of other colors too.

Bake the cakes in the oven for 25-30 minutes or until a toothpick comes out clean when inserted in the center.

Allow the cake to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.

When the cakes are completed cooled, use a cake leveling tool (or sharp knife) to remove the dome from the cake.* This is so there is a flat top for layering the cake with frosting.

To make the frosting, using a handheld or stand mixer, combine the softened butter, powdered sugar, and cream and beat until combined, smooth and stiff peaks form.

Scoop a half-cup of frosting into 7 bowls. Add gel food coloring to each of the bowls so that you have one of each color - sky blue, purple, pink, yellow, green, orange, and black. The rest of the frosting remains white.

To assemble the cake, place the first layer on a cake board (dab some frosting in the center of the board to stick the cake in place) and spread about 1 cup of frosting in an even layer.

Place the second cake layer and spread another cup of frosting in an even layer.

Place the third and final layer on top and frost the top and sides of the cake with the remaining white frosting. The sides of the cake do not have to be perfectly frosted as they will be covered with tie dye frosting, however, you will want a nice layer on the top of the cake. Place in fridge for frosting to firm up.

Place the black frosting into a piping bag fitted with a round no.3 piping tip. Set aside.

Place half of each of the frosting colors into a piping bag fitted with an open star tip. Set aside.

Using a knife, randomly place dollops of colored frosting around the sides of the cake. Use an angled spatula and lightly spread the frosting around the cake to create a tie-dye effect.

Using the bags of colored frosting, pipe swirls around the top of the cake in any order you like.

Using the bag of black icing, pipe peace signs of varying sizes randomly around the sides of the cake.

Place the icing flowers randomly around the sides and on the frosting swirls.

You can pipe a peace sign on the top of the cake or add some rainbow sprinkles to finish decorating the cake.

Chill before slicing and serving!