{happy birthday} How To Make a Super Cool Thomas the Train Birthday Cake

Let me give you a quick piece of parenting advice that I learned the hard way: do not let an almost-2-year-old browse train birthday cakes on Pinterest. If you do, be aware that he may come to his birthday party with some seriously lofty expectations! This is how we got to this point. Luckily my sister–who, FUN FACT, earned a trophy for cake decorating in the 7th grade–was there with her super steady hands, clear design eye, and patience to help me work this out.

My son is obsessed with the train worlds of Thomas and Chuggington, so I knew a train cake was in order. He’s also pretty into tunnels so this seemed like it fit the bill. If you’re not great at piping with frosting or simply aren’t interested in investing that kind of time, see my tips and shortcuts below for ways to get around it more quickly and easily!

Of course despite my best efforts my son insisted that Gator, some heretofore unknown character from the Thomas pantheon, had to be on the cake. So this actually became a Gator the train birthday cake. Whatever.

(And in case you’re wondering, last year it was a cat cake and the year before that, an automotive-themed number one cake.)

HOW TO: Make a Super Cool Thomas the Train Birthday Cake

  • Make a 2- layer cake in the flavor of your choice. Cook it in two 9-inch round pans.
  • Once cakes have cooled, put one layer on a plate and ice it with chocolate icing. I used a half recipe of Magnolia Bakery chocolate buttercream and made it pretty stiff. Reserve a very small amount of the chocolate frosting for making the tree trunk. Reserve a larger amount and use black paste food coloring to dye it black. This is what you’ll use for the tunnel and train tracks.
  • Decorate the entire rim of the cake with chocolate rocks and/or jellybean rocks. (I used a combination of both, and I got them at Powell’s Sweet Shoppe.)
  • Cut the second layer in half down the middle so you have two evenly sized half-circles. Place one on top of the frosted chocolate layer.
  • Now make vanilla icing. I used a full recipe of the Magnolia bakery vanilla buttercream and made it pretty stiff. Reserve a small amount and dye it green for the tree and flower stems. Dye a small amount dark blue for flowers. Dye the rest a very pale blue like the sky.
  • Ice the middle of the cake with light blue icing. Then put the other half circle on top and ice the entire thing with light blue, leaving a space on the front flat part for the tunnel. (It’s much easier to leave a space for the black frosting than to try and do it on top of the blue.)
  • Carefully fill in the tunnel shape with black icing. Decorate the tunnel seam with rocks.
  • Using a toothpick, put a few dots of dark blue on the sky part around the tunnel and smooth them in with a knife, to add a bit of color texture to the sky.
  • Use a pastry bag or Ziploc with the corner cut off to pipe the tree, track, and flowers with the green, blue, brown, and black icing. Write happy birthday on top. Decorate any unseemly parts with more rocks.
  • Put your child’s favorite train on the tracks!


  • If you don’t want to pipe flowers or write Happy Birthday, you can buy a sugar birthday topper and sugar flowers to stick on the cake, which would be a lot quicker and look terrific. Or you can buy candles that spell out Happy Birthday! For the train tracks, you could use Kit-Kats and black licorice vines if you don’t want to pipe them.
  • I like to use a small offset spatula for cake decorating. It is so much easier than a knife!
  • It’s best to use a dense cake, so cake mix is not the best for this. I use the Amy Sedaris vanilla cake recipe for my rainbow cakes, which also work better with a denser cake. I used this red wine chocolate cake recipe from Smitten Kitchen which was excellent in both texture and flavor, but I don’t know if all kids would like the flavor.
  • To make this a little easier, you could make all vanilla icing and dye some of it green or brown for the bottom layer. Then you don’t have to make two separate flavors of icing.
  • You can cover a lot of mistakes with the chocolate rocks. For example if the seam between the single and double layer is messy, you could just cover it with rocks and it would look great.
  • For the icing, err on the side of too stiff rather than too loose. Once you start moving it around, it will warm up and get smoother! You can always adjust icing stiffness with milk and powdered sugar – more milk if it’s too stiff, more sugar if it’s too loose.

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3 Responses

  1. Cousin Jamie says:

    You’d think our sons are related or something, with the love for Chuggington and tunnels (I nixed watching Thomas at home, but he does have some trains and books). Happy late birthday to Laz!

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