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Aero Mint Chocolate Cake

This chocolate marble cake is super-simple and sure to impress your friends.
Course Dessert
Cuisine American
Keyword cake, chocolate, loaf cake, mint chocolate
Prep Time 30 minutes
Cooking Time 45 minutes
Total Time 1 hour 15 minutes
Servings 12 people
Calories 490kcal


For the cake:

  • 250 g butter softened
  • 250 g caster sugar
  • 4 eggs large
  • 250 g plain flour
  • 3 tsp. baking powder
  • 4 tbsp. cocoa powder
  • 1 tbsp. milk
  • 1 tsp. vanilla extract
  • 1 tsp. peppermint extract
  • 3-4 drops of green gel food colouring

For the buttercream:

  • 100 g butter softened
  • 125 g icing sugar sifted
  • 1 tsp. peppermint extract
  • 1 tbsp. milk if required


  • Preheat the oven to 180°C, then line the base of a 2lb loaf tin with baking parchment and grease the sides with butter.
  • In a mixing bowl, cream together the butter and sugar until pale and smooth.
  • Next, add the eggs (beating well between the addition of each egg to avoid splitting. If the batter does split, don’t worry; the cake may not rise as much, but it will still be fine!)
  • Beat the mix until light and fluffy before folding in the flour and baking powder.
  • Remove half of the cake batter and place into another clean mixing bowl.
  • In the first bowl, fold the cocoa powder, milk, and vanilla extract into the batter to make your chocolate cake mix.
  • In the second, fold in the peppermint extract and gel food colouring to make the mint cake mix. I use gel food colouring as I find it creates a more vibrant colour and many are natural. Although, the natural colourings don’t always stay bright post-bake.

Let’s spoon and swirl!

  • In your prepared loaf tin, alternate between spoons of each mixture, dotting the two colours around the tin. Then, with a skewer or knife, swirl the two mixtures together to create a marble effect. Don’t overdo it though, or you’ll lose that marble effect.
  • Bake on the middle shelf of the oven for 45-50 minutes, until the cake is risen and a skewer placed in the centre comes out clean.
  • Leave the cake to cool in the tin fully before removing.

Icing on the cake…

  • In a mixing bowl, beat the slightly softened butter until pale and fluffy.
  • Add the icing sugar and fold together until the icing sugar is fully incorporated. (Try not to be too vigourous or you’ll be cleaning icing sugar off the kitchen surfaces for days!)
  • Add the peppermint extract, and beat for 5-10 minutes until you have a pillowy buttercream.
  • Spread the buttercream on the cake with an offset spatula (or a spoon!) and top with broken shards of Aero mint chocolate bar!