Preheat oven to 350°F.

Cream together the sugars and margarine until light and fluffy.

Add the eggs, one at a time, and then add the vanilla and water. Combine.

Add the potato starch, cake meal, salt and potato starch and mix until just combined.

Fold in the chocolate chips and the walnuts (if desired).

Spray a cookie sheet with nonstick cooking spray. Or, better still, line the cookie sheet with Gefen Easy Baking Parchment and spray with nonstick cooking spray.

Place the cookie dough in teaspoon-sized balls on the prepared cookie sheet, at least one inch apart.

Bake 12 to 15 minutes or until the cookies begin to brown around the edges.

Cool on a rack before storing in an airtight container.