Prep the pan and oven: Heat your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment, letting it hang over two sides for easy lifting.

Make the crust: In a bowl, combine almond flour, melted butter, and 2–3 tablespoons of your keto sweetener. Stir until it forms a damp, sandy mixture that clumps when pressed.

Press and par-bake: Firmly press the crust into an even layer in the pan. Bake for 10–12 minutes, until the edges look lightly golden. Set aside to cool slightly while you mix the filling.

Whisk the filling: In another bowl, whisk together eggs, the remaining sweetener (about 1/2 to 3/4 cup, to taste), fresh lemon juice, and finely grated lemon zest. Whisk until smooth and slightly frothy.

Adjust sweetness and tartness: Taste the mixture. If you like it brighter, add a little more zest or a tablespoon more juice. If you prefer sweeter, add a tablespoon more sweetener.

Pour and bake: Pour the filling over the warm crust. Bake 16–20 minutes, or until the center is just set and no longer jiggles when you gently shake the pan. Do not overbake or the bars may crack.

Cool and chill: Let the pan cool to room temperature, then refrigerate for at least 2 hours. Chilling helps the lemon layer firm up for clean slices.

Slice and serve: Use the parchment to lift the slab out. Slice into squares with a sharp knife, wiping the blade between cuts. If you like, dust the tops with a bit of powdered keto sweetener for that classic look.