Preheat your oven to 350°F (175°C) and prepare a round cake pan by greasing it and lining the bottom with parchment paper.

In a large mixing bowl, whisk together the eggs and sugar until well-combined and slightly frothy, about 2-3 minutes. Stir in the melted butter, lemon juice, lemon zest, and vanilla extract until smooth.

Sift almond flour, baking powder, and salt into the egg mixture, then gently fold until no lumps remain, forming a thick batter.

Fold in the chopped, toasted pistachios until evenly distributed.

Pour the batter into the prepared cake pan and smooth the surface with a spatula.

Bake for 45-55 minutes, until the edges are golden and the center is mostly set but still jiggles slightly.

Prepare the glaze by mixing lemon juice and sugar in a small bowl until the sugar dissolves.

Once the cake is out of the oven, spoon the lemon glaze over the top, allowing it to soak in, and sprinkle additional toasted pistachios on top.

Allow the cake to cool completely in the pan before transferring it to a wire rack.

Slice and serve at room temperature.