1. Preheat oven to 350 degrees. Spray two 8 inch cake pans with cooking spray and place a round sheet of parchment paper on the bottom of each pan. Set aside.
2. In a large bowl, add almond flour, sweetener, baking powder and salt. Stir to combine. Add egg yolks, sour cream, melted butter, heavy cream or nut milk and vanilla extract. Mix until combined. Set aside.
3. Add egg whites (all 6) into a clean large bowl. Using an electric mixer, start mixing slowly until frothy. Then increase the speed to high and beat until stiff peaks form.