Preheat your oven to 350F. Prepare the pie crust and lemon curd as directed.
Spread the lemon curd into the pie crust, filling it up to about 2/3 full.
In a large mixing bowl, beat the egg whites until stiff peaks form. Gradually add the powdered sweetener and cream of tartar, continuing to beat until the mixture is thick and fluffy.
Carefully spread the meringue over the lemon curd. Place the pie in the oven and bake for 5-7 minutes, or until the meringue is golden brown on top.