For the sponge:
225g plain flour
350g caster sugar
85g cocoa powder
1½ tsp baking powder
1½ tsp bicarbonate of soda
125ml vegetable oil
250ml boiling water
For the caramel buttercream:
100g butter, softened
150g icing sugar
100g caramel sauce, plus extra for drizzling
2 digestive biscuits, finely crushed
For the chocolate ganache:
100g milk chocolate, finely chopped
100g dark chocolate, finely chopped
200ml double cream
50g salted caramel sauce, warmed
3 squares of rocky road, chopped in small pieces
50g mini marshmallows
5 dark chocolate digestive biscuits
- Preheat the oven to 180˚C/160˚C fan/ gas mark 4. Line four 20cm cake tins with non-stick parchment paper.
- To make the sponge, combine all of the ingredients except for the boiling water into a large bowl. Beat together until the mixture is just combined. Add the boiling water, a little at a time, mixing and scraping down the sides of the bowl after each addition.
- Divide the mixture evenly amongst the tins and bake for 25-30 minutes, or until a skewer inserted in the centre comes out clean. Allow to cool completely.
- For the caramel buttercream, beat together the butter and icing sugar until smooth. Add the caramel sauce and beat again until combined. Stir in the crushed digestive biscuits.
- For the ganache, place both chocolates in a heatproof bowl. In a saucepan, heat the cream to just before boiling point, then pour it over the chocolate. Leave for 30 seconds, then stir well to create a thick glossy ganache. Leave to cool, then whisk with an electric mixer until the ganache forms a thick buttercream consistency.
- To assemble the cake, place the first sponge layer on a cake stand or serving plate. Spread over some of the caramel buttercream and place the next sponge on top. Continue to stack and spread each of the sponges.
- Use a palette knife or offset spatula to spread half of the ganache over the top and sides of the cake, making sure to fill in any gaps. Refrigerate the cake for 30 minutes.
- Once set, spread over more ganache to cover any crumbs, then smooth the icing.
- Drizzle some caramel sauce around the top edge of the cake. Decorate the top with rocky road pieces, mini marshmallows, and dark chocolate digestives.
Per Serving 597kcals, 31g fat (14.5g saturated), 79g carbs (52.2g sugars), 6.6g protein, 3.6g fibre, 0.284g sodium