Preheat the oven to 350°F.

In a stand mixer or bowl, combine the cake mix, pudding mix, eggs, milk, oil, and food coloring (either pink or blue).

Beat on medium speed for 2 minutes until fully combined.

Bake for 20-25 minutes or until a toothpick inserted in the center comes out clean.

Let the cakes cool, then remove them from the pans. Wrap in plastic wrap and freeze for easier frosting.

In a stand mixer, beat the room-temperature butter until pale and almost white.

Add the vanilla extract.

(Optional) Add a tiny amount of purple food coloring using a toothpick to brighten the white frosting. Start with less than a drop and adjust as needed.

Gradually add 2 cups of powdered sugar and mix until smooth.

Add the cream and mix well.

Add 1-2 cups more of powdered sugar until the frosting reaches your desired consistency.

Place a small amount of buttercream in the center of your cake board to hold the cake in place.

Unwrap one frozen cake layer and place it on the cake board. Apply a thin layer of frosting to seal the crumbs, smoothing the edges.

Add ¼-½ inch of frosting on top of the first layer and smooth it out.

Place the second cake layer on top and apply another thin layer of frosting (crumb coat). Chill the cake in the fridge or freezer for 5-10 minutes.

Divide the remaining frosting in half. Color one half pink and the other blue.

Using a piping bag, pipe pink rosettes(or design of choice) around the base and top of the cake, leaving spaces for blue rosettes.

Switch to blue frosting and pipe rosettes into the remaining gaps.