Preheat the oven to 350 degrees.

Add 1 cup of the almond flour, ¼ cup of the sugar substitute, ½ cup butter, and 1 teaspoon of the vanilla to a mixing bowl. Beat until well combined.

Spread the mixture evenly into the bottom of a well greased 9x9 baking dish.

Bake for 10-12 minutes until the edges are golden.

Mix together 1 cup of almond flour, ½ cup of sugar substitute, 3 large eggs, 1 tsp of vanilla, and the zest and juice from two large lemons until smooth and well combined.

Pour the mixture carefully and evenly over the crust in the baking dish, then bake for 25-30 minutes until cooked through.

Sprinkle with additional confectioners sugar substitute if desired before serving.