Bake chocolate cakes as per the link above.
Allow the cakes to cool to room temperature.
While the cakes are baking and cooling, prepare the pink and blue frostings.
Remove cake from pans and trim the domes (if any) so they are flat.
Place one cake on a serving dish.
Spread blue icing evenly on top with a spatula. If the gender of the baby is a girl, then spread pink icing instead. I was making this cake for a boy.
Place the other cake on top of the icing and press gently to secure properly.
Use a spatula to spread pink and blue icing randomly on top of the cake and along the sides of the cake.
Use a clean spatula to spread this frosting smoothly until you have a swirled pattern of both colors. Both colors should be prominent and should not completely blend in together.
Cover the entire cake in sanding sugar. Remove excess sugar from the serving dish with a clean paintbrush and keep aside in a sealed Ziploc bag for another cake decorating project.
Use a dollop of buttercream to stick large candy balls along the top outer edge of the cake.
Push the cake topper in the middle of the cake. Enjoy!