Pre-heat the oven to 350F. Gather and prep all ingredients. Powder the erythritol (for the filling) using a spice grinder or a food processor. Zest and juice the lemons.

Make the crust by mixing together almond flour, erythritol, and butter.

Spoon the crust mixture into a parchment-lined ramekin, casserole dish, or muffin tray and press against the bottom to make a smooth surface. Bake in the oven for 15-20 minutes or until the crust is golden brown.

As the crust cools some, start on the filling. Whisk together the eggs, powdered erythritol, almond flour, lemon juice, lemon zest, and a pinch of salt. Mix until smooth.

Pour the lemon filling onto the semi-cooled crust and return to the oven, baking for 15-20 minutes. The center should be slightly jiggly but the top set completely. If you overbake it, it will crack.

Place the bars in the refrigerator for 3-5 hours to cool completely and firm up. Optionally dust with additional powdered erythritol and enjoy!