JP recently turned 3 and he loves diggers. He loves looking at them, playing with them and reading about them. I now know a surprising amount about different diggers. I also find myself completely entranced as Joe and I watch real ones moving earth and creating piles. It looks like such a skill. Sometimes they almost have a ballet like quality, the way they move. So you can see there wasn’t really much of a decision to make about what kind of cake he would like. For the past two years though, he has had fruit cakes, but this year he was very clear it needed to be a chocolate cake. So a chocolate sponge digger birthday cake it had to be.
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This recipe is a Victoria sponge cake with cocoa added. The cocoa gives it a great chocolate colour and a great chocolate taste for little taste buds. But it’s not a deeply rich indulgent chocolately chocolate cake. We have known little taste buds to find this too rich. (But if you are after one of those, then this one looks pretty good to me.
The chocolate ganache in this recipe is where this cake is dreamy. The ganache will sandwich the cakes together, instead of using buttercream which would more usually do this job. Buttercream is an enormous amount of icing or confectioners sugar and unsalted butter, beaten together. It is delicious but it’s super sweet; for a chocolate version, cocoa or melted chocolate is added. Chocolate ganache, on the other hand, is an equal quantity of chocolate and hot double or heavy cream which melts the chocolate. You leave this mixture to set hard and then beat with an electric whisk until it has the consistency of buttercream. It’s properly chocolatey, because it’s 50% chocolate and you can use whatever chocolate you like. We went for dark cooking chocolate with 54% cocoa solids. This meant it wasn’t too dark for our young audience, but nor was it too sweet for the adults in the room. It was a great ganache, super simple to make and it worked for all the audience both old and young.
The ganache also made great mud and to which I added chocolate chunks, not chips. A serious digger challenge!
For the observant ones among you, you’ll recall that I normally suggest using Madeira cake if you are going to cover in fondant icing. We went for a Victoria sponge recipe for this cake. Did the cake come crashing down under the weight of the fondant icing? No it did not. It was absolutely fine and so I have to rethink that advice. Victoria Sponge or Madeira cakes will be fine under fondant icing.
This recipe involves making three cakes of different sizes. Normally, when I make one sponge cake, I make the mixture and divide it between two and then use icing to sandwich them both together. This method wasn’t going to work given I have one oven and three cakes to make. I’ve listed the ingredients for each cake below so you could make them all separately and divide the mixture across two cake tins. If you do this remember to reduce the cooking time, I suggest by a half and then take it from there.
When making a sponge cake it’s important not to open the oven too early – this disrupts the oven’s temperature and can cause the cake to sink in the middle. See my blog post on cakes that sink. The issue here is that when cooking the three cakes together the smallest cake is done after 25 – 30 minutes whereas the biggest one takes an hour. This wasn’t a problem when I made this cake, but it’s something to be aware off. Get that first cake out the oven as quickly as you can and get the door shut!
I was surprised how long the 4 inch cake took to cook as it’s seriously small. But having all three cakes in the oven at one time increases the cooking time needed for each.
Having sandwiched the cakes together with the ganache we (read Dave) then covered them in shop bought fondant icing. If you haven’t used fondant icing before, read my ‘How to ice a cake using fondant icing’ and ‘7 tips for a stress free kids birthday cake with fondant icing’ posts.
Digger Birthday Cake – 3 tier chocolate sponge with chocolate ganache and fondant icing
You’ll need a little extra butter to grease the tins. The ganache goes in the middle and on top of the cakes. This recipe makes 2kg of chocolate ganache. 200g of it is reserved for the ‘mud’ and also the ‘glue’ sticking the largest cake to the cake stand. The rest is divided between the three cakes.
We use Renshaw pre-made and pre-coloured icing to keep life as simple as possible. We have tried supermarkets brands but they don’t have the same vibrant colours.
- Prep Time: 2 hours 30 minutes
- Cook Time: 1 hour
- Total Time: 3 hours 30 minutes
- Yield: 40
- 540g unsalted butter
- 540g caster sugar
- 9 large eggs
- 540g self raising flour
- 4 ¼ tsp baking powder
- 4 ½ tbsp cocoa
3 cake tins – 4 inch, 7 inch and 8½ inch
Chocolate ganache and icing
Making the cakes and ganache
- Preheat the oven to 180°C / 160°C fan / 350°F / Gas mark 4.
- Grease and line the cake tins.
- In a large bowl beat the butter until it’s soft with an electric whisk or a strong arm and wooden spoon. Add the caster sugar and beat until combined and the mixture has turned a pale yellow colour. This may take up to a minute of beating and the aim is to get lots of air into the mixture.
- Add an egg or two at a time and beat well to combine.
- In a separate bowl mix the flour, baking powder and cocoa.
- Sift the flour on top of the butter mixture and use a metal spoon to fold the flour into the butter mixture. Stop mixing the moment the flour is combined, as further mixing can remove the air you added earlier.
- Using the metal spoon, spoon the required mixture into the three baking tins. The 4″ cake needs 238g of mixture, the 7″ cake 714g and the 8½” cake 1190g. Gently smooth the top and put straight into the preheated oven.
- The 4″ cake will take about 25 – 30 minutes, the 7″ cake 45 minutes and the 8½” cake an hour. The cakes are done when they have shrunk back from the side of the tin, spring back under the weight of your finger and an inserted skewer comes out clean. Resist the temptation to open the oven door early.
- While the cakes cook, make the ganache. Break up the chocolate into squares and put into a large bowl. Heat the cream until hot but not boiling and then pour over and melt the chocolate. Once all the chocolate is melted leave to cool (not in the fridge as this tends to make it too hard). Once solidified, beat with an electric whisk until light and fluffy.
- When the cakes are done, leave in the tins for 15 minutes to cool and then remove onto a cooling rack. If not icing immediately, once cool, cover in cling film to seal out air.
Icing the cakes
- Using a bread knife or cake wire, cut the cakes in half horizontally.
- Start with the largest cake.
- Put 1/2 tablespoon of ganache on the cake stand. Then place the bottom half of the largest cake on top but to the back of the cake stand sufficient to ensure you can get a digger in front. The ganache is there to hold the cake in place. Now add 500g of ganache to the cake and even it out. Top with the top half of the second cake, topping that with another 500g of ganache.
- Place the bottom half of the 7 inch cake in position and spread over 300g of ganache. Then add the top half and again cover with 300g of ganache.
- Position the bottom half of the 4 inch cake and spread on 100g of ganache. Top with the final piece of cake and cover in another 100g. Leave for 30 minutes somewhere cool to allow the ganache time to firm up a bit. Meanwhile roll out the icing.
- Measure from the bottom of one side of the cake to the bottom of the other side. Roll the green icing again on icing sugar to this height making sure it doesn’t get less than 4mm thick. Ensure it’s wide enough to cover the whole cake.
- Warm the raspberry jam for 15 seconds in the microwave and paint the cake which doesn’t have ganache on it. Then using four hands carefully place the green icing first up the straight side of the cake, over the top of it and then generously down the other side, so there is enough spare icing to cover each step of the cake. Take time to carefully cover all of the cake and get rid of any excess icing.
- Decide on the height of the gray boulder. Measure to the top of the second cake and then on a work surface liberally covered in icing sugar roll out a piece of grey icing boulder shape to that height, ensure it’s no less than 4mm thick. Use the rest of the grey icing to make little rocks. Paint raspberry jam where you want the boulder to go. Stick the boulder on, again four hands is useful for this point.
- Spoon out parts of the cake that the diggers will be ‘working on’. Spread on chocolate ganache and decorate with chocolate chunks, grey boulders and the diggers themselves.