Preheat the oven to 350 degrees F. In a large bowl, whisk together the almond flour, sugar and salt. In a small microwave safe bowl, melt the butter. Stir the melted butter into the flour mixture, until you have a crumbly texture. Press the mixture into a 9 in pie shell, or spring form cake pan. Press evenly along the bottom, and up the sides. Pierce the bottom with a fork, then bake for 16 minutes. Carefully remove from the oven and set aside. In a blender or food processor, mix together the cottage cheese, greek yogurt and cream cheese. Add in the sugar substitute, vanilla, salt, zest & juice of two lemons. Mix together. Last, add in the eggs and preferred thickener. Mix until you have a smooth texture. Pour the mixture into your pie shell. Bake at 350 degrees for 50 minutes. Remove and let cool completely on a wire rack. Garnish with powdered sugar substitute if desired.