Food / 29 May, 2025 / Ellie Thompson

Watercolour Layer Cake

This watercolour layer cake is a real showstopper, but it’s made easy by using fuss-free M&S sponge cake mix, Madagascan vanilla icing, food colouring gels, and Percy Pig sprinkles.

Ingredients

• British butter for greasing or oil
• (400 g) M&S sponge cake mix
• 3 medium eggs
• 100 g unsalted British butter, softened
• 100 ml milk
• 2 tubs (800 g) Madagascan vanilla icing as needed
• Blue colouring gel as needed
• Green colouring gel as needed
• Yellow food colouring as needed
• Red colouring gel
• 1 tub (75 g) Percy Pig party sprinkles
• 75 g white chocolate broken into pieces
• 1 tub (52 g) mini meringue

Method

Making sponge cake

Preheat the oven to 180°C/160°C fan/gas mark 4. Prepare the cake tins by greasing them with butter (as needed) and lining the bottom with a circle of baking parchment and the sides with strips to prevent sticking.

Prepare the sponge mix (1 pack) according to the packet instructions using free-range eggs (3), unsalted butter (100g), and milk (100ml). Divide equally into the cake tins and bake for approximately 30-35 minutes, until the cakes are golden, cooked through, and a cake tester or cocktail stick comes out clean from the centre.

Leave to cool for 5 minutes. Turn out onto a wire rack, remove the paper and let cool completely.

If your sponges have a little bump from where they have risen, trim this away with a cake leveller or bread knife before stacking and filling, to keep your cakes level. Using a cake turntable is really helpful in getting this to look neat. If you don’t have one, you can put your cake board on top of a dinner plate to spin the cake on. You can also use a microwave plate.

Place the bottom layer onto a piece of baking parchment larger than the cake and secure with a dab of frosting onto a plate or board. Then add a little bit of frosting on top of the paper to keep the cake stuck in place once it’s chilled.

Icing the sponge

Spread over a layer of icing (2 tubs) right to the edges of the sponge.

Top with a second layer of sponge, ensuring it aligns with the one below. Repeat this process with a layer of icing in the same manner. Make sure it looks straight, then press down gently to fix it in place.

Place the last layer on top, inverting it so that the smooth and flat part faces upwards, not the trimmed part (this keeps it neater and less crumbly). With a palette knife, generously spread icing all around the sides to fill in the gaps between the sponge layers. This allows you to hold the top of the cake still while you work around it. Use gentle pressure against the side of the cake with the palette knife and use a back-and-forth spreading motion to spread the coating over the sides.

Once the sides are covered, spread a thin, even layer over the top.

Once the cake is covered, clean the palette knife and go around the cake again to smooth off the excess icing. Any excess can be scraped off the knife and reapplied where needed. Chill in the fridge for around 30-40 minutes, or to speed things up, pop in the freezer for 15 minutes.

Let’s get creative!

To create the watercolour layer, mix the pastel colours first by putting 4 dollops of icing and a couple of teaspoons of each colour around the edge of a plate.

Squeeze over a couple of drops of green colouring gel (as needed), yellow food colouring (as needed) and blue colouring gel (as needed) and mix in with a cocktail stick or the end of a little spoon. For the pink, add a few drops of red colouring gel (as needed) and a drop of blue and mix to create a dusky pink shade.

Remove the cake from the fridge. Add a small dollop of icing to the middle of a plate or cake stand, and then lift the cake onto it.

Use a palette knife to load the rest of the uncoloured vanilla icing on top of the cake.

Use the knife at a 30-degree angle to spread the icing evenly over the top, pushing it in a side-to-side motion with firm pressure to ensure an even spread. The icing will start to push out over the edge, and as this happens, you can change the angle of your knife to be vertical to neatly cover the edges.

Now spread little flat dabs of colours all over the cake until it’s dotted with splodges of pastel icing.

To achieve the watercolour effect, spread the paint once more gently over the top and sides to blend the colours together slightly and create a flat finish.

Here come the Percy Pigs!

Arrange the Percy sprinkles (1 tub) to the bottom section of the watercolour layer cake. Place in the fridge for about 15 minutes to chill.

Heat the white chocolate (75 g) in the microwave for 30 seconds at a time until melted and lump-free, or melt in a bowl over a pan of boiling water. Allow the chocolate to cool slightly.

Use a piping bag or teaspoon to create a drip effect with the white chocolate over the top and sides of the cake.

Drizzle the extra chocolate over the meringues (1 tub) and add Percy sprinkles. Arrange the meringues on top of the cake and serve.

Article by M&S Food.

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