I baked this Nail Polish Birthday Cake for my niece's 8th birthday party, which she chose to have a pedicure party theme for. We found plates and napkins in bright pink with zebra print trim, and I used those for the icing colors (her favorite color is hot pink).
I baked two store bought mixes (marble) in extra deep 9 inch round cake pans and let them chill in the fridge overnight. I made up my buttercream icing the same night to let it set up in the fridge also. I found a recipe for the icing on the internet. Then I used Wilton food coloring in rose and black to tint the icing. It worked out really well.
So the next morning, I iced the middle of the two layers and stacked them ontop of each other. I used a cake leveler by Wilton to trim the rounded top off the top layer of the cake, then did a crumb icing very thin in pink, and let that set for 30 minutes. Then I did the heavier icing trying to keep it as smooth as possible. Once that icing layer had set for 30 minutes as well I used the Viva paper towel trick I saw online to smooth the icing as much as possible. It worked pretty well.
I had some trouble finding something for the lid that would be the correct proportion. My sister in law suggested a black koozie that was on the counter, and it was perfect! I slipped it onto a small plastic juice glass and frosted right over it, repeating the paper towel step on it as well. Then I used an icing bag with the line tip to write "Aubrie's Pretty in Pink #8" since my niece was turning 8.
She really loved it and all the guests thought it was cute. I had fun making it and I've had more fun the last few weeks looking at all the great cakes on this site, so thanks to everyone for all the great tips! I hope this will be helpful to someone.!