Thomas mountain cake with moving train!

Thomas cake with tunnel branded copyThis year was the second year in a row that Crackers has had a Thomas the Tank Engine-themed birthday party. For his third birthday we did the train cake, so this year we decided to step it up to another level – literally. Enter the four-storey-high Thomas mountain cake with tunnel and moving train!

I’m not going to lie – being a cake-making novice, this was a pretty ambitious undertaking. But I have to say, both Crackers and I were pretty chuffed with the end result! (See clip below for our creation in action. The first cake you see the train go through here was actually our practice cake – totally stale and inedible by that point, but it still looked ok so we thought ‘why not?’)

What you will need:

For the cakes
(ingredient quantities are for a single cake, we made four cakes)

  • 20cm round cake tin
  • cake cooling rack
  • cakeboard
  • electric cake mixer
  • baking paper
  • 250g flour
  • 250g butter
  • 250g sugar
  • 250ml eggs (approx. 5)
  • 50g of cocoa powder
  • 2tbsp milk
  • two Thomas train tunnels (Ours were from the wooden train sets you can get from Kmart. If you don’t have wooden tunnels, you could just ‘wing it’ for size – the cakes will be firm enough to hold without the tunnels in them.)
  • wooden skewers
  • a bread knife for carving the tunnel
  • smaller knife for carving crevasses

For the ganache icing

  • 500ml cream
  • 660g good quality cooking chocolate
  • blender
  • saucepan
  • spatula
  • heat-proof mixing bowl

For the decorative icing
(you may need two batches of this)

  • 1 cup icing sugar, sifted
  • 1 egg white (have an additional egg on hand to thin out the icing if needed)
  • blue food dye
  • green food dye
  • spoon
  • piping bag

To finish

  • tracks
  • battery-operated train
  • Lego man construction worker and sign (optional)
  • crumbled chocolate/Maltesers for ‘rubble’ (optional)


1. Bake the cakes.
Preheat oven to 185°C (165°C for fan-forced). Grease cake tin and line with baking paper. Cream butter and sugar until white and fluffy. Beat in eggs, a bit at a time, then fold in the flour, cocoa and milk. Beat until smooth. Bake for 35 mins or until skewer comes out clean and cake bounces back when pressed gently in the middle. (NOTE: You can get away with three cakes, like we did for our practice version, but four looks more impressive! Let your cakes completely cool before you try to carve them, preferably overnight. If you want to make your cakes well in advance, you can actually freeze them but make sure they are thoroughly defrosted before you add any icing.)

2. Carve the tunnel.
Stack the cakes on top of each other (you only need to work with the ones you need to carve for the tunnel at this stage – 2 was enough for us), place a cake cooling rack on top and flip them over so you’re carving from the flattest side. Insert two wooden skewers to keep them in place as you carve. If you have wooden tunnels, place them on the top of the stack and carve lines into your cake on either side of the tunnels to use as a guide. Using your bread knife, carve the tunnel out of the cake until the wooden tunnels fit (or until you think it’s the right size, if you don’t have tunnels). Then, place the cakeboard on top of the stack and flip it back to right-side-up so you can begin carving out the crevasses. For a video clip on how to flip the cake stack over, click here.

Carving the tunnel

3. Sculpt the mountain.
To turn your cake stacks into something resembling a mountain, you’ll need to carve crevasses into it, using your smaller knife. Don’t be shy here – you have to cut quite a bit out of the cake for it to look realistic. Keep the offcuts though, as you can use these to give your mountain a broader and more realistic shape around the bottom. We also used some offcuts on the top, to give the cake a pointier peak. Don’t worry if it looks a bit piecemeal at this stage – the ganache should fix that.

sculpting the cake

The image on the left actually shows our practice cake – with the real one (right) I cut the pieces off in much bigger chunks to begin with so they could be added back in later to give the mountain a more realistic shape.

4. Add ganache.
To make the ganache, break your cooking chocolate up into pieces and throw them in the blender. Blend them up until they’re well crumbled (warning: this is noisy!). Put the chocolate in your heat-proof mixing bowl. Bring cream just to the boil in a saucepan and then pour it over the chocolate. Stir until combined and smooth. While the ganache is still warm and runny, pour it over your mountain in dollops with a large spoon. (Tip: To keep your ganache runny, sit the bowl over another bowl full of hot water. Just be careful not to get any water in the ganache or it will spoil.) Cover up your cake board with ganache too (you can cover this with green icing later if you want to). Let the ganache dry completely before moving on to the next stage. (The ganache should be hard enough that you can make a ‘tapping’ noise on it and it should not be sticky.)


5. Decorate the cake.
Mix up the egg white and icing sugar to make up white icing. This is what you will use for the snow at the top and the base coat of your waterfall. You want the icing to be slightly thicker for the snow than the waterfall. Use a spoon to drizzle the icing over the cake. Once you’ve done the white bits, separate out some of the icing and add a small amount of blue food dye. While the white part of the waterfall is still wet, add a dollop of blue. The blue should mix in with the white to give a flowing waterfall appearance. You should also get a bit of a ‘pool’ at the bottom. Once you’ve done this, go back to the white icing and add some green food dye for the green foliage. You’ll probably need to add a bit more icing sugar here to thicken it up. Use the piping bag to add the foliage and try to avoid mixing it with any still-wet icing already on the cake. The green also works well around the base of the cake to tidy up any rough edges.

Decorating mountain cake

6. Add your Lego man and any other embellishments. A tip-truck could also work here – maybe even add some bits of crumbled chocolate or Maltesers for rocks?

7. Build the track around your mountain (if you’re not using track tunnels you’ll obviously need to build some straight track through your tunnel). Add battery-operated train and you’re off!
We also made Thomas the Tank Engine gingerbread biscuits for the party. To see how to make these, click here.

This recipe was part of Kitchen Fun With My 3 Sons’ ‘Kitchen Fun and Crafty Friday’ link-up party #162 (24 April) – we’re link number 85! Click on the button below to check out heaps of other really cool crafty ideas from this link-up party!



4 thoughts on “Thomas mountain cake with moving train!

    • Thanks for your comment Carlee. It was lots of fun and you don’t have to be a cake-making guru to do it either – I am certainly not! The beauty of it is that a real mountain is pretty messy and irregularly shaped so there’s no pressure to make it look too perfect. That’s my kind of cake!

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