I made this Princess and the Pea cake for my daughter’s first birthday party, last year. I used a boxed cake mix and baked it in a 1″ cookie sheet pan. I cut the cake into rectangles to be the mattresses.
I used a can of whipped white frosting and separated in to six different little bowls. Made each bowl a different color. Each mattress was frosted with a different color and decorated with a tube of colored icing. I used two big marshmallows for the pillows and a green M&M for the pea. Topped it off with a Polly Pockets doll.