Ingredients

Step by step

1. Preheat the oven to 180°C, fan 160°C, gas 4. Grease the base of two 20cm round cake tins and line with baking paper. In the bowl of a stand mixer (or in a large bowl and using an electric hand mixer), beat the butter and caster sugar together until very light and creamy. Add the eggs, one at a time, beating well after each addition. Fold through the flour and salt, then stir in the yogurt and grapefruit zest and juice until combined. Divide the mixture between the prepared tins and bake for 30 minutes, or until golden and a skewer inserted comes out clean.
2. Put all the ingredients for the drizzle into a small pan and bring to a simmer for 5 minutes. Pour into a bowl to cool.
3. Use a skewer to poke holes all over the surfaces of the warm sponges, then brush generously with the drizzle. Leave to cool in the tins for about 30 minutes, then remove from the tins and transfer to a wire rack to cool completely.
4. For the meringue buttercream, put the egg whites and sugar in a large heatproof bowl set over a pan of barely simmering water. Use a balloon whisk to whisk for 5-8 minutes until the sugar has dissolved and the mixture is warm – it should look like runny cake icing (and read 60°C on a cook’s thermometer). Transfer the mixture to the bowl of a stand mixer (or a clean, cold bowl and using an electric hand mixer), and whisk on high for 5-6 minutes or until it forms stiff, glossy peaks and the mixture has cooled. Reduce the speed to low and add the butter, one small piece at a time, making sure each has been incorporated before adding the next. When all the butter has been added and the mixture is smooth, whisk in the grapefruit zest and a pinch of salt. Let the buttercream chill for up to 20 minutes to allow it to firm up to a spreadable consistency.
5. To assemble, place one of the sponges on a cake stand or serving plate and spread with some of the buttercream. Top with the other sponge layer. Cover the top and sides of the cake with a thin layer of buttercream – this stage doesn’t need to be neat, it’s just to catch all the crumbs. Chill in the fridge for 20 minutes (along with the remaining buttercream). Meanwhile, using a sharp serrated knife, remove the peel and pith from the zested grapefruit. Slice into rounds, cut in half and set aside. Cover the chilled cake in another layer of buttercream, using a palette knife to smooth it out. Arrange the grapefruit halves on the cake and scatter over lime zest to serve. Store the cake for 3-4 days in an airtight container in the fridge.
   Paloma

   Makes 1. Dampen the rim of a tumbler by rubbing a grapefruit wedge around the edge, then dip it into a small plate of sea salt flakes. Pour 50ml of tequila, 60ml of pink or red grapefruit juice, 2 teaspoons of agave syrup and 2 teaspoons of lime juice into a cocktail shaker. Fill with ice, then shake until cold. Strain into the prepared glass, add some ice cubes, then top up with soda water. Garnish with a wedge of grapefruit.