For my son's fifth birthday he requested a Mach 5 race car from the Speed Racer movie. I was a little nervous at first but I was very proud of the end result of this Racer Race Car Birthday Cake.
I made the cake using 2 - 13x9 cakes (2 box cake mixes). I layered the two cakes on top of each other with a thin layer of icing between them. I then shaped them both to look like the Mach 5 car, using a sharp knife (I used my son's toy car as a reference). I used the scraps from shaping the larger cakes to build up certain areas to make it look like the car.
After shaping the car I frosted the whole thing with canned white frosting, using a regular butter knife. I cut out the wheel wells so I could put Ding Dongs in as the tires. I put the cake in the fridge so that I would be able to pipe a smooth coat of white frosting over the rough frosting coat.
After chilling it for a couple of hours I piped the white frosting on using a wide flat tip. After letting the frosting harden for a few minutes I used my fingertips to smooth out the edges and blend them together. I used black food coloring to make gray/silver frosting and used a fine piping tip to create the hubcaps on the Ding Dong wheels.
I used white frosting to attach the wheels into the wheel wells. I used red frosting and red sugar crystals to create the seating area of the car. I then used a piece of plastic (that I washed thoroughly) to form the windshield. I used yellow and red icing in a tube to make the details on the car.
I chilled it overnight in the fridge and after setting it on the table I piped on Happy Birthday. He loved it and now wants a Mach 6 for his 6th birthday!