Preheat your oven to 250°F. Line one baking sheets with parchment paper. Trace three, 6-inch circles onto the parchment, then flip the parchment over so the marked side is facing down.
In a clean mixing bowl, beat the egg whites and cream of tartar until foamy.
Gradually add the sugar, a little at a time, and continue beating until the meringue is thick, glossy, and holds stiff peaks. add vanilla extract and mix in.
Gently mix in cornstarch and lemon juice.
Gently fold in the roughly chopped pecans.
Divide the meringue evenly between the three prepared circles and spread each one into an even layer.
Bake until the layers are dry, crisp, and lightly golden, ~1 hour and 30 minutes. Turn off the oven and let the meringue layers cool inside with the door slightly open.