Preheat the oven to 160°C fan/180°C conventional/355°F and grease and line 2 x 20cm loose-based round cake tins with non-stick baking paper. Set aside.

In a large bowl with a handheld mixer or a stand mixer fitted with the paddle attachment, cream together the butter and sugar for about 3-5 minutes until lighter in colour and smooth. Add the vanilla extract and mix again.

Add the eggs, one at a time, whisking until the batter is completely smooth.

In a food processor or blender, grind the pistachios into a fine crumb.

Sift in the flour and baking powder, then add the salt and ground pistachios. Fold in carefully until just combined.

Divide the batter equally between the two prepared tins and smooth over the surface with a spatula.

Bake for about 35 minutes, or until a skewer inserted into the centre comes out clean. Remove from the oven and leave to cool in the tins for 15 minutes before turning out onto a wire rack to cool completely.

Meanwhile, prepare the buttercream: in a large bowl cream together the softened butter and sifted icing sugar until pale. Add the pistachio cream, salt, and lemon juice. Beat again.

Once the cakes are completely cooled, place one on a flat plate. Pipe half the buttercream on top. Spread the raspberry jam on top, avoiding the edges.

Top with the second cake and use the remaining buttercream to cover it.

Decorate with fresh raspberries, sprigs of fresh mint, and chopped pistachios.