Easy Rainbow Cake

Ingredients

FOR THE CAKE

• 125 g unsalted butter, softened, plus extra to grease
• 150 g caster sugar
• 2 medium eggs
• 100 g sour cream
• 1/2 tsp. vanilla extract
• 150 g self-raising flour
• 50 g strawberry jam
• Large pinch of salt

FOR THE BUTTERCREAM

• 225 g unsalted butter, softened
• 400 g icing sugar
• 1 tsp. vanilla extract
• 1 tbsp. milk

FOR THE DECORATION

• Skittles, around 320g
• 100 g white marshmallows

Directions

1. Grease and line a 20.5cm (8in) round cake tin. Preheat the oven to 180°C (160°C fan). 
2. In a large bowl, using a hand-held electric whisk, combine the butter and sugar until light and fluffy, around 4 to 5 minutes. Add the eggs one at time, beating well after each addition. Add the sour cream, vanilla and a large pinch of salt. Fold in the flour. Add the mixture to the tin and spread out evenly.
3. Bake for 25-30 minutes until a skewer inserted into the middle comes out clean. Cool in tin for 10 minutes then turn out onto a wire rack to cool completely.
4. To make the buttercream, beat the butter until light and fluffy, around 4 minutes. Add the icing sugar a bit at a time, beating well after each addition to incorporate. Add the vanilla, milk and a large pinch of salt. Leave to one side.
5. Once cooled, cut the cake in half down the middle, so you have two half moons. Place one half on a cutting board and spread with the strawberry jam. Sandwich the other half on top. Spread a small amount of the buttercream along the cut side of the cake.
6. Carefully transfer the cake stack to a serving platter or cake board, cut side down.  Spread the buttercream evenly all over the sides and top of the cake in a thin crumb coat. Put into the fridge for 30 minutes to firm up. Spread the remaining buttercream evenly over the cake.
7. To decorate, sort the skittles into different colours and arrange on both sides of the cake, working your way from the outside in, in this order – red, orange, yellow, green, purple. Cover the top in the same way as the sides.
8. Arrange the marshmallows in a cloud shape at the two ends of the rainbow on the cake on both sides, tearing them up if desired to create different shapes. Serve in slices.