Preheat the oven to 350°F (175°C). Grease a round cake pan and line the bottom with parchment paper.

In a large mixing bowl, whisk the eggs with the sugar until blended. Stir in the melted butter (or oil), lemon juice, lemon zest, and vanilla until smooth.

Add the almond flour, baking powder, and salt to the wet mixture. Stir until the batter becomes lump-free.

Fold in the chopped pistachios to evenly distribute them throughout the batter.

Transfer the batter to the prepared pan and level the surface with a spatula.

Bake for 45–55 minutes, or until the cake's edges are golden and the center is set.

While the cake is still warm, combine the lemon juice and sugar in a small saucepan and heat gently until the sugar dissolves.

Spoon or drizzle this syrup over the top so it soaks in, then scatter the extra pistachios on the glazed cake.

Let it cool completely before slicing so the texture sets.