How to Make a Rainbow Layer Cake My Baba 12 August, 2018 Food, Recipes I’ve been meaning to try my hand at making a rainbow layer cake with the kids for quite some time, so I’ve finally dug out the recipe, made a trip to my local specialist cake shop for the colouring gels, and have everything prepped to try this out on the weekend. It looks delicious, I can hardly wait! Prep: 1 hours 30 minutes Bake: 45 minutes Serves: 16 Ingredients: 375g butter (unsalted) 675g plain white flour 450g unrefined golden caster sugar 9 eggs 3 tsp 3/4 tsp 3 tsp 6 gel or paste colours of food colouring For the buttercream: 350g butter (unsalted) 700g icing sugar 2 tsp vanilla extract Method: Step 1: Preheat the oven to 180c (fan 160c, gas mark 4). Grease and base line 2 20cm/8 inch round sandwich tins Step 2: To make the sponge layers you need to split the ingredients into three. Put 125g butter, 225g flour, 150g golden caster sugar, 3 eggs, 1tsp baking powder, 1/4tsp salt, 1tsp vanilla extract in a large mixing bowl and beat until smooth. Next you need to split this mixture evenly into 2. It’s best to do this on the scales so you know it’s evenly split. Step 3: Put the 2 halves of batter into separate bowls then add your chosen colour and mix. Keep adding the colour until you are happy you have the right shade. Step 4: Then pour the batter into the prepared tin and place in the oven for 12-15 minutes or until a skewer comes out clean. Step 5: Remove from the oven and leave to cool for a while then turn out onto a wire rack to cool. If you leave the sponges to cool upside down they should flatten out into even layers. Step 6: Then repeat from step two twice for the remaining four layers, using the remaining colours. Step 7: To make the buttercream, beat together the butter and icing sugar until pale and fluffy then add the vanilla extract. Step 8: To construct the cake take a cake stand or cake board and smear a little of the buttercream onto the sponge, and then carefully place the next layer centrally on top. Repeat this with the rest of the layers. We started with red, then orange, yellow, green, blue and finally purple. Step 9: Spread a thin, even layer of buttercream onto the sponge and then carefully place the next layer centrally on top. Repeat this with the res of the layers. We started the red, then orange, yellow, green, blue and finally purple. Step 10: Finally cover the top and sides of the cake with a thick layer of buttercream using a palette knife, being careful not to get any crumbs in the buttercream. Step 11: Leave the cake to set for about 1 hour before presenting or serving.