Preheat the oven to 180°C/356°F (no fan). Line a 10 x 22 cm (4 × 8-inch) baking pan with parchment paper.
Put 200 g butter (softened), 175 g sugar and the zest of one lemon in a mixing bowl. Cream together with an electric mixer or wooden spoon until smooth and slightly paler.
Add the 4 small eggs one at a time, mixing each egg in fully before adding the next.
Stir in 1 tsp vanilla essence.
In a separate bowl, whisk together 80 g flour and 1 tsp baking soda.
Add the flour mixture to the wet mixture along with 80 g ground roasted pistachios and 80 g ground raw almonds. Fold everything together gently with a spatula using wide up-and-down motions until just combined — avoid overmixing.
Pour the batter into the prepared pan and smooth the top. Bake in the preheated oven for 50 minutes, or until a toothpick inserted into the center comes out clean.
Remove the pan from the oven and let the cake rest in the pan for 15 minutes, then transfer the cake (still on the parchment) to a wire cooling rack. Remove the parchment and cool the cake completely on the rack.
While the cake cools, make the frosting: beat 50 g butter (softened) with 250 g cream cheese and 70 g powdered sugar until smooth and spreadable.
When the cake is completely cool, spread the cream cheese frosting evenly over the top. Slice and serve.