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Mars Bar Cake

Chocolate, caramel buttercream frosting and mars bar nougaty goodness layered between chocolate cake - are we in heaven... or at a child's birthday?!


  • Ganache
  • 600g dark chocolate
  • 300ml thickened/whipping cream
  • Caramel Ganache
  • 250ml thickened cream
  • 100g unsalted butter
  • 660g) white sugar
  • 250ml water
  • 2 tbs glucose syrup (or corn syrup)
  • 1 teaspoon sea salt flakes
  • Frosting
  • 2 batches Swiss meringue buttercream frosting (recipe:
  • Cake
  • 100g cocoa powder
  • 350g all-purpose flour
  • 1 tsp salt
  • 1 tsp bicarbonate of soda
  • 450g caster sugar
  • 350g unsalted butter, softened
  • 4 large eggs, at room temperature
  • 350ml milk
  • Extra stuff
  • 60 mini mars bar chocolate bars (yes, I did actually use this many lol)
  • caramel sauce
  • mini choc chips


  1. Ganache
  2. Add chocolate and cream into a large microwave safe bowl. Microwave for 20 seconds at a time, mixing each time until smooth. Cover with plastic wrap and set aside to set.
  3. Alternatively you may melt it using a double boiler. Fill a medium sized pot with 1/3 of the way with water. Bring to a boil. Place bowl with chocolate and cream over the top and gently mix until mixture is completely melted and smooth. To soften the ganache to spreading or piping consistency microwave for 10 seconds at a time, mixing each time with a large spatula until it reaches the right consistency.
  4. Caramel Ganache
  5. Place the sugar, glucose syrup and water in a large saucepan over low heat. Bring to a boil and cook for 10–12 minutes, without stirring until it becomes a deep caramel colour.
  6. Remove from the heat and add the salt, cream and butter and whisk to combine. Allow to cool completely before using. Guys be super careful when you add the butter and cream to the hot caramel. I’d recommend melting the butter and I’d also recommend heating the cream to avoid splattering.
  7. Frosting
  8. To prepare frosting add a spatula full of the ganache to the caramel ganache and mix until really well combined. Then add the rest of the frosting and mix to combine. You’ll need to freshly whip it up before using :0)
  9. Cake
  10. Please note: the cake recipe will need to be doubled to achieve the cake in the video. I halved it in the video because most people don’t have mixing bowls big enough in their kitchens to make the entire recipe in one go :0) Let’s get stuck into the recipe!
  11. Preheat a fan-forced oven to 160C (320F) or 180C (356F) for a conventional oven. Spray an 8” cake tin with oil spray and line the bottom with baking paper.
  12. In the bowl of a stand mixer fitted with the paddle attachment, add the flour, bicarb soda, caster sugar and salt. Turn mixer on low speed and allow it to mix for a couple minutes to help everything combine well (alternatively you may do this by sifting the ingredients together). Add the softened butter and mix until it resembles a fine sand like texture.
  13. Add the milk and eggs into the bowl with the dry ingredients and mix on medium speed until no dry ingredients are visible. Scrape down the bowl and mix for another 20 seconds.
  14. Fill three 8” cake tins with batter.
  15. Bake for 30 min or until a toothpick inserted comes out clean. Allow the tins to cool for 2 min and then carefully flip the cake tins over on to a cooling wrack to cool completely before using.
  16. Using a large serrated knife, carefully trim the top off each layer of cake to make even and flat layers. Try to aim to get them all the same height. An easy way to do this is to find the lowest height of the cake, place a skewer or toothpick next to that point and mark it. As you go around each side of the cake cutting it, use the marked skewer to make sure each cut is at the same height.
  17. To prepare crumb coat, add a dab of frosting onto an 8” cake board or serving plate. Add first cake layer. Guys make sure the chocolate cake is chilled when you put it all together to avoid the cake from collapsing.. Use a small offset to add a layer of frosting and smoothen out and layer the frosting on each layer before adding mars bar chocolates into the frosting. Add the next layer of cake and repeat with all the layers until you get to the top. Add more frosting around the outside to fill the grooves between each layer. This should just be a neat thin layer of frosting which is aimed at trapping any cake crumbs so that random bits of cake crumbs don’t show up on the outside of the cake. Chill for 2 hours or overnight
  18. Add a layer of softened ganache using a small offset spatula or piping bag. Use a cake scraper to smoothen out the ganache around the sides. Then smoothen out the top using the cake scraper. Chill.
  19. To finish the cake add mini choc chips down the bottom of the cake. Drizzle with caramel sauce. Fit the end of a piping bag with a Wilton 8B tip and frost swirls of frosting on top. Drizzle the swirls with caramel and top with mars bars.