Preheat your waffle iron: Set it to medium or medium-high. Lightly grease it if needed.
Whisk the dry ingredients: In a large bowl, combine flour, protein powder, cinnamon, baking powder, baking soda, salt, and sugar. Break up any lumps.
Mix the wet ingredients: In another bowl, whisk eggs, milk, Greek yogurt, oil, and vanilla until smooth.
Bring the batter together: Pour the wet mixture into the dry.
Stir gently until just combined. If it seems too thick to pour, add 1–3 tablespoons of milk to loosen. The batter should be thick but scoopable.
Rest briefly: Let the batter sit for 3–5 minutes.
This helps the flour hydrate and improves texture.
Cook the waffles: Add batter to the preheated iron, using the recommended amount for your model. Close and cook until deeply golden and crisp, usually 3–5 minutes.
Keep them crisp: Place finished waffles on a wire rack instead of stacking. Stacking traps steam and softens the edges.
Serve warm: Top with a dollop of Greek yogurt, a drizzle of maple syrup, and fresh fruit.
Add a sprinkle of cinnamon for extra aroma.