Heat the oven to 180C/160C fan/gas 4. Butter three 18cm sandwich cake tins and line with baking parchment. Beat together the butter, sugar, eggs, vanilla, baking powder and flour using a stand mixer or electric hand whisk until you have a fluffy mixture, about 5 mins. Fold in the white chocolate until it’s well distributed throughout.

Divide the mixture evenly between the tins and level out using a palette knife or the back of a spoon until smooth. Bake for 25-30 mins until a skewer inserted into the middle comes out clean. Remove from the oven and leave the sponges to cool in the tins for 10 mins, then remove from the tins and transfer to a cooling rack, top side down, and leave to cool completely. If the sponges are not level use a serrated knife to cut away the peaks.

While the sponges are cooling, make the ganache. Put the white chocolate in a large bowl. Pour the cream into a saucepan over a medium heat and bring to a simmer. Immediately pour the cream over the chocolate and leave to stand for 4-5 mins until the chocolate has melted. Mix together to form a smooth ganache, ensuring all the chocolate has fully melted, then mix in the vanilla. Chill in the fridge for 30 mins, stirring occasionally so it doesn't completely harden, until spreadable and thick enough to coat the cake.

Once the sponges are cool and the ganache has set to a spreadable consistency, you can construct the cake. Place one sponge on a serving plate, spread over a thin layer of the chocolate ganache, then fill the middle with a third of the raspberries. Place another sponge on top and repeat with a layer of ganache and another third of raspberries. Put the final sponge on top and gently coat the whole cake with a thin layer of ganache. Leave in the fridge to set for at least 20 mins. To finish, spread over any remaining ganache and top with the remaining raspberries. Will keep chilled for up to three days in an airtight container.