This took a bit of research. I wanted the cake to be as realistic as possible so i needed to know what wheels and trucks look like. I decided to use Rice Krispies Treats (RKT) covered in fondant.
Prior to assembley, I added HAPPY 7TH BIRTHDAY to each wheel in place of a brand name.
Now that the hard part was out of the way. it was time to assemble the cake. I used a 1/4 sheet cake and 1 9" round cake cut in half.
I carved the rounds a bit to give the allusion of the ends being curved down as if the board we upside down. Then it was time for icing and fondant. I made a batch of Marshmallow Fondant (the fondant of choice for children's cakes since it tastes so much better).


I used an edible metallic spray paint to make the trucks look metal. assembled the trucks and wheels using dowel rods and royal icing. Then added other fondant details. Finishing it off with a 7 in the middle.
I was so nervous about it falling apart, but it held up like a champ. Franklin loved it and had a great birthday!!