Preheat the oven to 400F. Grease a silicone mini muffin pan with non-stick spray.

Briefly whisk the egg whites and water together, then pour or spoon into the muffin pan cavities. You only need to just cover the base of each one. You may have a little of the mixture left over.

Sprinkle some grated Parmesan into each cavity.

Bake for 8-10 minutes until they have turned crisp. Note: They burn easily so keep an eye on them!