Lemon, blueberry and coconut cake

Method

1. Heat the oven to 180°C/160°C fan/gas 4. Using the stand mixer, beat the 250g butter and 500g sugar until pale and fluffy. Whisk in the lemon zest and juice, then whisk in the eggs, a little at a time, until fully incorporated. Whisk in the desiccated coconut and coconut milk.
2. Sift in the flour and baking powder, then beat until just combined with no lumps. Don’t worry if the mixture looks curdled – it will come back. Toss 300g blueberries in 2 tbsp flour so they’re lightly coated (this helps stop them sticking to the bottom while baking), then gently fold into the batter.
3. Divide the batter evenly among the 4 tins, then bake for 25-30 minutes until golden brown and a skewer pushed into the centre comes out clean. Leave to cool in the tins for 15 minutes, then turn out onto a wire rack to cool completely. Once cooled, use a serrated knife to level the top of each cake.
4. For the lemon cream cheese icing, beat the 75g butter and 175g cream cheese in the stand mixer. Add the icing sugar in a few goes, beating to ensure there are no lumps. Add the lemon zest and juice, beating until smooth, then set aside until you’re ready to assemble the layer cake.
5. For the swiss meringue buttercream, first make a blueberry purée. Put 350g of the blueberries and 3 tbsp water in a pan on a medium heat and bring to the boil, stirring occasionally. Simmer for 10 minutes, then remove from the heat and leave to cool fully (see Make Ahead).
6. In a large bowl set over a pan of simmering water (don’t let the water touch the bowl), whisk the egg whites with the 340g sugar, whisking continuously so the eggs don’t cook, until all the sugar has dissolved (about 10 minutes). The mixture should reach 72°C on the thermometer. When you can no longer feel any grains of sugar as you whisk, the meringue is ready. Transfer it to the stand mixer, then keep whisking on a high speed until stiff peaks form and the bowl isn’t hot to the touch.
7. Switch to the paddle attachment, then start adding the butter in small pieces. Be patient with this, as sometimes it can look as though the mixture is curdling, but it will be okay. Add the vanilla, then keep beating until you have a silky buttercream.
8. Slowly add about half the cooled blueberry purée. You can strain it to remove the skins, but I keep them in to add flecks of colour. Add the purée until you get a lovely violet colour – reserve the rest for decoration.
9. To assemble the cake, put a spoonful of lemon icing in the centre of a plate or cake stand, then set one sponge on top. Spread with a third of the icing, then top with a second cake layer and repeat until all the cakes and icing have been used up.
10. Spread a thin, see-through layer of the buttercream (about 200g, known as a crumb coat) all over the cake, then chill for 30 minutes until set firm. Finish the cake with the remaining buttercream, smoothing the top and sides as you go for a smart finish. Toss the remaining 70g blueberries in the reserved blueberry purée, then spoon onto the cake to finish.