My 2 year old son loved tractors (still does). It was his first word besides mom and dad. So a tractor cake it was for his birthday! This was my first time making a 3D cake. It turned out exactly how I was hoping. I used this site for inspiration photos! I'm a firm believer that cakes can look good and taste good without icky fondant. So my cakes are made with homemade cake and butter cream icing.
I made one 13x9 and two loaf pans of chocolate cake. I cut the hump off the cooled 13x9 cake, cut in half, and stacked together for the trailer. It was placed on an aluminum foil wrapped 6pk package of chocolate bars (what I found in my kitchen that was the right size) to get it 'off the ground'. For the tractor, I used one loaf cake for the bottom. I cut the hump off only half of it, so the 'hood' would have some shape to it. On the front half where the hood was going, I cut almost an inch off each side. For the cab, I cut a square out of the center of my second loaf cake, again, leaving the hump on it for shape. I used icing to glue them together, and placed it on an aluminum wrapped 2pk of pectin (again, what I found in my kitchen that was the right size) to get it 'off the ground'.
I iced each separately before joining together, crumb coat first, then top coat. I used two bendy straws to look like a trailer hitch to join them together. I then used some icing to glue my 'tires' on - little chocolate donuts for the small tires, and two large donuts for the large tires. The large tires were a type of donut that had a 'tread' look to the edge, but they ended up being too soft and looking a little smashed. And once I iced them, you couldn't see the 'tread pattern' anymore.
For his next birthday I made a backhoe, and used the donuts that are just like the small ones here, but are large size (they come in a pack of 3 chocolate, 3 plain, and 3 powdered). Then, I used some yellow dyed butter cream for the hub caps, added a plain border of green around the top and bottom of the trailer, personalized the top, added a 'grill' and low lights with white icing, and used peanut butter m&ms for the rest of the lights. The smoke stack was a cut off straw covered in icing.
My son LOVED his green tractor and trailer cake! (oh, and he said, "Where's the loader?" when he first saw it.