Mix butter, 1 cup almond flour, ¼ cup erythritol, and a pinch of salt. Press evenly into an 8x8" parchment paper-lined baking dish. Bake for 20 minutes at 350 degrees F. Then, let cool for 10 minutes.
Into a bowl, zest one of the lemons, then juice all 3 lemons, add the eggs, ¾ cup erythritol, ¾ cup almond flour & pinch of salt. Combine to make filling.
Pour the filling onto the crust & bake for 25 minutes.
Serve with lemon slices and a sprinkle of erythritol.
