Preheat oven to 300 degrees F. Line a baking sheet with parchment paper, lightly spray with cooking spray and set aside.
In the bowl of a stand mixer, whip egg whites until frothy. Add in cream of tartar and beat until soft peaks form. Slowly sprinkle in truvia bit by bit with mixer on and beat until egg whites are firm and will hold their shape.
Spread egg whites onto baking sheet into a large, even, 10 to 12 inch circle. Bake 45 minutes, then turn oven off and keep meringue inside to cool completely and dry out. While meringue is baking, wash and hull strawberries. Cut into pieces and toss with truvia and vanilla. Cover and refrigerate.
Once meringue has cooled, remove from oven and use a spatula to remove from parchment paper. Place onto serving platter. Top with cool whip and strawberries. Cut into 10 pieces and serve.
The more accurate macros for 1 serving (1/10th of this recipe) are as follows: 87 calories, 24g C/2g P/3g F.