Preheat your oven to 350°F (175°C) and grease the cake pans.

In a mixing bowl, cream together the butter and sugar until light and fluffy.

Add the eggs one at a time, beating well after each addition, then mix in the vanilla extract.

In a separate bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with milk, beginning and ending with the flour mixture.

Divide the batter equally into three bowls.

Add a few drops of pink food coloring to one bowl, purple to the second, and blue to the third, mixing until the colors are evenly distributed.

Pour each colored batter into separate cake pans and bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Let the cakes cool in the pans for 10 minutes, then turn them out onto a cooling rack to cool completely.

Whip the heavy cream until stiff peaks form, then divide it into three bowls and tint each with a drop of the respective food colorings.

Place the pink cake layer on a cake turntable and spread a layer of pink whipped cream on top.

Add the purple cake layer, spread purple whipped cream, and then top with the blue cake layer.

Cover the whole cake with a thin layer of blue whipped cream to create a crumb coat, then chill for 20 minutes.

Once chilled, apply a final layer of ombre whipped cream, blending the colors slightly for a gradient effect.