Prepare the Sponges: Preheat your oven to 180°C (160°C fan/Gas Mark 4). Grease and line the bases of three 20cm (8-inch) round cake tins with parchment paper. In a large bowl or stand mixer, cream the softened butter and caster sugar together for about 5 minutes until pale and fluffy.

Mix the Batter: Beat in the eggs one at a time, adding a tablespoon of the flour with the last egg to prevent curdling. Stir in the vanilla bean paste. Sift the flour and baking powder into the bowl, then gently fold it in using a large metal spoon, alternating with the milk until just combined. Be careful not to overmix.

Bake the Cakes: Divide the batter evenly between the three prepared tins and level the tops with a spatula. Bake for 25-30 minutes, or until a skewer inserted into the centre comes out clean. Let the sponges cool in their tins for 10 minutes before turning them out onto a wire rack to cool completely.

Make the Raspberry Coulis: While the cakes are cooling, place the raspberries, sugar, and lemon juice in a small saucepan. Heat gently over a medium heat, stirring occasionally, for 8-10 minutes until the raspberries have broken down and the sauce has thickened slightly. For a smooth coulis, you can press it through a fine-mesh sieve to remove the seeds. Set aside to cool completely.

Create the Buttercream: Melt the chopped white chocolate in a heatproof bowl set over a pan of simmering water (or in the microwave in 30-second bursts). Set aside to cool for about 10-15 minutes until it's barely warm to the touch. In a stand mixer, beat the softened butter for 5 minutes until very pale and creamy. Gradually add the sifted icing sugar, beating well after each addition. Add the vanilla and the cooled, melted white chocolate and beat until smooth and combined. If it's too stiff, add a tablespoon of milk. If you want to learn more about the science of a good frosting, this guide on making buttercream is a great read.

Assemble the Dream Cake: Place one sponge layer on your serving plate. I find that creating a 'dam' of buttercream around the edge of each layer is crucial. Pipe a ring of buttercream around the perimeter, then spoon about half of the cooled raspberry coulis into the centre.

Layer and Crumb Coat: Place the second sponge on top and repeat the process: pipe a buttercream dam and fill with the remaining coulis. Top with the final sponge layer. Apply a very thin layer of buttercream all over the cake—this is your 'crumb coat'. It traps any loose crumbs. Chill the cake in the fridge for 30 minutes.

Final Decoration: Once the crumb coat is firm, apply the remaining buttercream over the top and sides of the cake, using a palette knife or cake scraper to get a smooth or textured finish, as you prefer. Decorate with fresh raspberries and white chocolate shavings.