In a large mixing bowl, whisk together the protein powder, flour, baking powder, and salt until evenly combined.

In a separate container, combine the water, egg whites, yogurt or applesauce, and your chosen sweetener. Stir until fully blended.

Carefully pour the wet mixture into the bowl of dry ingredients and gently stir until just incorporated.

Preheat your waffle iron according to the manufacturer's instructions and coat with nonstick cooking spray.

Once preheated, pour the batter into the center of the hot waffle iron and cook for about 5-7 minutes.

Remove the first waffle, re-grease the iron, and repeat cooking until all the batter is used up.

Serve your protein waffles warm, topped with your favorite additions like fresh fruit or nut butter.