For the Cake:
For the Lemon Cream:
To make the cake, preheat the oven to 325°F. Butter a 4-by-8-inch loaf pan. Line with parchment paper (the parchment will stick to the butter keeping it in place).
In a food processor, combine the pistachios and almonds and pulse until finely ground. Set aside.
Beat the butter and sugar in the bowl of a stand mixer fitted with the paddle attachment until smooth. Grate the zest from the lemons directly into the bowl. And beat until combined. Mix in the vanilla extract just until incorporated. On low speed, gradually add the ground nuts and mix just until incorporated. Then add the eggs, one at a time, mixing after each addition just until incorporated. Stir in the flour and salt and mix just until incorporated.
Spoon the batter into the prepared loaf pan. Bake until a skewer inserted into the middle of the cake comes out clean, about 60-75 minutes. Let cool in the pan on a wire rack for 10 minutes. Then, tapping the pan, invert the loaf onto the wire rack peeling the parchment off.
To make the lemon cream, using an electric mixer, whisk the cream until thickened and about the consistency of Greek yogurt. Stir in the lemon juice and sugar.
Serve each slice of loaf with a dollop of cream and scatter with pistachios.