Step 1

Preheat the oven to 375 degrees F (190 degrees C). Generously grease a 12-cup muffin tin with cooking spray.

Step 2

Combine egg whites, Greek yogurt, salt, black pepper, garlic powder, onion powder, oregano, and cayenne in a bowl; whisk until smooth and no lumps remain. Mix in red bell pepper, spinach, and Cheddar cheese.

Step 3

Divide egg mixture between the 12 muffin cups, filling until almost full.

Step 4

Bake in the preheated oven until egg bites puff up substantially and begin to brown, 20 to 25 minutes. Allow to cool for 5 minutes; bites will deflate substantially at this time. Run a knife around the edges and bottoms to loosen and remove from the cups. Allow to cool to room temperature.