Preheat your oven to 160°C (fan)/180°C (conventional) or 355°F. Grease and line two 20cm round cake tins with parchment paper.

In a large mixing bowl, cream together the softened unsalted butter and golden caster sugar until light and fluffy, which should take about 3-5 minutes.

Mix in the vanilla extract, then add the eggs one at a time, whisking after each addition until smooth.

Finely grind the shelled pistachios to a flour-like consistency. Sift together the plain flour, baking powder, and fine sea salt, then fold into the creamed mixture with the ground pistachios.

Divide the batter evenly between the prepared tins and smooth the tops. Bake in the preheated oven for about 35 minutes or until a skewer comes out clean.

Let the cakes cool in their tins for 15 minutes, then transfer to a wire rack to cool completely.

For the buttercream, whip the softened butter and sifted icing sugar until pale and fluffy. Add the pistachio cream, a pinch of salt, and lemon juice, then mix until creamy.

Once cool, place one cake layer on a serving plate. Spread half the buttercream, then a layer of raspberry jam. Top with the second layer and spread the remaining buttercream over the cake.

Decorate with fresh raspberries, mint sprigs, and chopped pistachios, then slice and serve.