Pistachio cake

1. Heat the oven to 180C/160C fan/gas 4. Butter and line a 23cm springform tin. Blitz 150g of the pistachios in a food processor until finely ground, tip into a bowl and stir through the flour, baking powder and a pinch of salt. In a separate bowl, beat the butter and sugar until pale and fluffy, around 5 minutes. Add the eggs one at a time, beating well for a minute after each, then beat in the vanilla and gently fold through the flour mixture. Spoon carefully into the tin and bake for 35 to 40 minutes, until a skewer comes out clean. Leave to cool completely in the tin on a wire rack.
2. Meanwhile, sift the icing sugar into a bowl and add the mascarpone, double cream and pistachio paste. Beat together until smooth, then chill for 20 to 30 minutes so it thickens to a spoonable consistency.
3. Using a serrated knife, slice the cooled cake in half horizontally to give two layers. Sit the bottom layer on a plate, spread over a generous spoonful of the pistachio cream and scatter on a good handful of raspberries. Set the second sponge on top, then coat the top and sides with the rest of the cream. Finish with the last raspberries, the remaining pistachios and a little lime zest. It keeps in the fridge in an airtight container for two days.

Tips from the ZestyPlate Kitchen

• Grind the pistachios finely but stop short of them turning oily, which would weigh the sponge down.
• Cream the butter and sugar until really pale and fluffy; this is what gives you a tender, well-risen cake.
• Wait until the cake is stone cold before filling, otherwise the cream will simply slide off.
• A short spell in the fridge firms the pistachio cream to an easy spreading texture.