Preheat the oven to 350°F and line an 8X8 inch baking pan with parchment paper. Set aside.
For the crust: In a food processor, add the almond flour, melted butter, powdered erythritol vanilla extract and a pinch of salt. Process until a dough forms. You can use a hand mixer.
Evenly press the dough into the pan and bake until lightly golden brown, about 15 minutes. Once cooked, let cool for at least 30 minutes.
Prepare the filling: Juice all the lemons and add them to a medium bowl.
Over the lemon juice, add the room temperature eggs, the sweetener, lemon zest and whisk for 30 seconds. Don't use a hand mixer because overmixing the ingredients will turn your keto lemon bars will crack when baked.
Stir in the almond flour and pour the topping over the cooled crust whisking while pouring to ensure that all the ingredients are evenly combined.
Bake for about 25 minutes or until the filling has set.
Let it cool completely before slicing. Refrigerate for at least 2 hours before slicing. Use a sharp knife to cut them into squares. Enjoy!