Ingredients

Step by step

1. Preheat the oven to 180°C, fan 160°C, gas 4. Grease and line 2 x 18cm round deep cake tins. Melt the butter and add the milk, then set the mixture aside.
2. Put the eggs and sugar in the bowl from a stand mixer (or a large heatproof bowl) and set over a pan of just simmering water. Beat until the sugar has dissolved and the liquid is lukewarm. To test if the sugar is dissolved, rub some mixture between your fingers – if it feels grainy, keep beating. Transfer the bowl to the stand mixer and whisk for 6-8 minutes or until the mixture has cooled, tripled in volume and leaves ribbons when you move the whisk through it.
3. Add around a third of the flour and fold in carefully using a spatula, ensuring there are no flour pockets. Repeat with another third and finally the last third, taking care to not knock out too much air.
4. Drizzle the melted butter mixture down the side of the bowl and fold again to incorporate, along with the vanilla extract. Divide the mixture between the prepared cake tins and bake for 30-35 minutes or until golden and a cake skewer inserted into the centre of the cakes comes out clean. Leave to cool in the tins for 15 minutes, then turn out onto a wire rack to cool completely.
5. To make the buttercream, first put the blueberries in a pan with the elderflower cordial and bring to the boil. Reduce to a simmer and cook for 6-8 minutes or until the blueberries have completely broken down. Remove from the heat and blitz to a purée. Pass through a sieve to remove any skins, pressing to extract all of the fruit. Leave to cool completely.
6. Put the egg whites and sugar in the bowl from a stand mixer and again set over a pan of just simmering water. Whisk until the sugar has dissolved and the mixture is lukewarm. Transfer the bowl to the stand mixer and whisk for a further 10 minutes, until it’s meringue-like and at room temperature. Add the soft butter, 10g at a time, beating well between each addition, then whisk in the vanilla.
7. Divide slightly less than a third of the buttercream between 2 separate bowls. Add a little of the blueberry purée to one bowl and whisk until it is a pale pink colour (1-2 tablespoons). Add the remaining purée to the second bowl and whisk until you have a darker colour.
8. Slice each of the cakes in half horizontally and then put one layer on a cake stand or plate. Spread with some of the darkest buttercream and then place the next layer on top. Spread this layer with a little of the paler pink buttercream, then top with the next layer. Spread with some plain vanilla buttercream and finish with the final cake layer.
9. Working from the top down this time, mirror the graduated colours of the sandwiched icing on the outside of the cake, starting with a ring of vanilla buttercream at the top, followed by the pale pink icing in the middle, and finishing with the darkest colour around the base. Smooth the remaining vanilla buttercream over the top of the cake and then use a palette knife around the circumference of the cake to blend the colours together, giving an ombré effect.