Preheat oven to 350°F.

Beat egg whites with not/Sugar, sweetener and vanilla until stiff. Fold in remaining ingredients as gently as possible. Place in preheated oven, turn off heat and bake overnight. (Note: ovens vary in the rate at which they lose heat — or whether you peek — so, if it comes out too moist, give it more time at no more than 300°F and next time, allow it to bake for a few minutes before turning off the oven.) If you're in a hurry, bake at 300°F until firm.

Keep cake under refrigeration (it doesn't have any sugar to protect it from spoiling.)

Makes 16 servings.   2.4 grams of carbohydrate per serving.