You don’t need to run out to the bakery and order a fancy, specialized cake in order to have something fun and inventive. Using just cake mix and frosting in a can, you too can create an affordable yet adorable themed cake. I made this for a baby shower, but be creative with other shapes you can make! I recommend testing out making the shapes with a piece of paper first so you can feel confident when you have the cake in front of you.
1 (15.25-ounce) box white cake mix
Vegetable oil and eggs as needed according to package directions
2 (12-ounce) jars buttercream frosting
Sprinkles and/or icing for decorating
Preheat the oven to 350°F. Coat a 9 x 13-inch baking dish with cooking spray.
Prepare the cake according to the package directions. Bake and cool.
Trim the top of your cake flat and flip it onto a platter.
Cut a half circle from the middle of one of the short ends of the cake. This will be the onesie's neck hole. Then, cut rounded corners off the opposite end of the cake to make the onesie's leg holes.
Discard (or nibble on) the neck cut-out, but save the leg cut-outs to make the onesie's sleeves. Trim the edge of the cut-outs, so they’re flat. Place the cut edges against the sides of the cake, lining the corners up with the top edge of the cake. You now have your onesie's shape!
Ice the cake with buttercream frosting and coat the freshly iced surface with a layer of sprinkles.
Place extra frosting into a piping bag and outline the edges to clearly define the onesie’s shape. Continue decorating as desired. Slice and serve.
If you are a visual learner, like me!, here are the steps to success. Have fun!