Step 1: Preheat the Waffle Iron: Turn on your waffle iron to a medium-high setting. Allowing it to get fully hot before adding the batter ensures that your waffles will have a nice crisp on the outside while remaining tender on the inside.
Step 2: Mix the Dry Ingredients: In a medium-sized bowl, whisk together the protein powder, oat flour, baking powder, cinnamon, and salt. Mixing the dry ingredients first helps prevent clumps and ensures the leavening agent is evenly distributed.
Step 3: Combine with Wet Ingredients: Add the liquid egg whites, Greek yogurt, and vanilla extract to the dry mixture. Stir everything together until a smooth batter forms. If the batter seems too thick, you can add a tablespoon of water or almond milk to reach your desired consistency.
Step 4: Let the Batter Rest: Let the batter sit for about 2 to 3 minutes. This allows the oats to hydrate and the baking powder to activate, which results in a much fluffier waffle.
Step 5: Cook the Waffles: Lightly coat the waffle iron with cooking spray. Pour half of the batter onto the center of the iron and close the lid. Cook for 3 to 5 minutes, or until the steam stops escaping and the waffle is golden brown. Repeat with the remaining batter.