Rocky road cake recipe

(58 ratings)

This delicious rocky road cake combines the best bits of everyone's favourite traybake with a deliciously soft sponge.

rocky road cake
Preparation Time25 mins
Cooking Time55 mins
Total Time1 hours 20 mins
Nutrition Per PortionRDA
Calories585 Kcal29%
Fat27 g39%
Saturated Fat11 g55%
Carbohydrates77 g30%

This rocky road cake is any chocolate lover’s dream - the basic sponge is enhanced with chewy cranberries, chocolate chips and mini marshmallows.

Small chunks of broken biscuits add a really lovely texture to the chocolatey sponge. Our rocky road cake has a melted marshmallow topping that makes it so eye catching, too. It's quite quick to make - under an hour and a half, plus you'll need some time for it to cool properly before you ice it. It serves 6 people and makes a lovely birthday or special celebration cake for anyone who is a fan of chocolatey treats. Perfect with a big afternoon mug of tea.


  • 60g unsalted butter
  • 60g vegetable oil
  • 25g cocoa powder
  • ½ tsp bicarbonate of soda
  • 180g caster sugar
  • 150g plain flour
  • 1 free range egg
  • 60g buttermilk
  • 40g dried cranberries or raisins
  • 50g white chocolate chips
  • 100g broken digestive biscuits
  • 20g mini marshmallows

To decorate:

  • 30g white chocolate, melted
  • 30g dark chocolate, melted
  • 20g mini marshmallows




  1. Pre-heat the oven to 200ºC. Place the butter, oil and cocoa powder into a medium pan and heat gently until the butter has melted. Remove from the heat and allow the mixture to cool then add 125ml of water, bicarbonate of soda, sugar, flour and a pinch of salt and whisk to combine.
  2. In a separate bowl beat the egg with the buttermilk. Add the mixture from the pan and combine, next add the cranberries, chocolate chips and biscuit pieces through the mix.
  3. Pour the mixture into the prepared tin and sprinkle 20g marshmallows on top.
  4. Bake for 45-55mins, remove from the oven when an inserted knife comes out clean, allow the cake to cool in the tin, run a knife around the edge before turning out.
  5. Using a spoon drizzle the melted chocolate over the cake and top with mini marshmallows.

Top tip for making rocky road cake

If you prefer you can substitute the buttermilk for natural yoghurt.

How can I make my own buttermilk?

It's so easy to make your own buttermilk substitute at home. Use the same amount of full fat milk, then stir in 2 tbsp lemon or lime juice and leave it for 10 minutes or so at room temperature. The milk will froth up slightly and become buttermilk.

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Rose Fooks
Deputy Food Editor

Rose Fooks is Deputy Food Editor at Future Publishing, creating recipes, reviewing products and writing food features for a range of lifestyle and home titles including GoodTo and Woman&Home. Before joining the team, Rose obtained a Diplome de Patisserie and Culinary Management at London’s Le Cordon Bleu. Going on to work in professional kitchens at The Delaunay and Zedel.