Crust:
Preheat the oven to 325F and line a 9×9 square baking pan with parchment, leaving an overhang for easy removal. In a large bowl, combine the almond flour, sweetener, cinnamon, vanilla extract, and salt. Stir in the melted butter until well combined. Press into the bottom of prepared baking pan. Bake 12 to 15 minutes, until just beginning to brown on the edges. Remove and let cool while preparing topping.

Filling:
In a small saucepan, bring the cream to just a simmer. Remove from heat. Add the chocolate chips and let sit 5 minutes to melt, then whisk in until smooth. Spread over the cooled crust and refrigerate until firm, about 1 hour.

Topping:
Preheat oven to 300F. In a large bowl, beat the egg whites with cream of tartar and salt until frothy. With beaters going, slowly add the sweeteners and vanilla extract and continue to beat until stiff peaks form. Spread over the cooled filling, swirling with a spoon to make peaks. Bake 20 minutes or until topping is golden and just barely firm to the touch. Refrigerate at least another hour to firm up, then gently lift out by parchment paper edges and cut into squares.