Preheat oven to 375 F. Beat egg whites till fluffy. With the whisk going, slowly add 3/4 cup sugar and beat until stiff peaks form(stiff peaks are when you lift the whisk out and the peak of white stays in place).

Whisk the egg yolks with remaining 3/4 cup sugar, potato starch, coconut flakes, and lemon juice. Gently fold in the egg whites to the yolk mixture. (Fold by pulling the spatula through the batter in the shape of a "C", and pulling the batter up at the end. You want to use light folds so the batter stays airy.) Continue until the yolks and whites are fully combined.

Pour the batter into a 9'13 inch pan fitted with a piece of parchment paper. Sprinkle with chocolate chips. Bake for one hour, checking with a toothpick at 45 min. to test for doneness.