Preheat oven to 375°F (190°C). Grease a muffin tin with cooking spray or butter.
Whisk together the eggs and milk in a mixing bowl—season with salt and pepper.
Dice the bell pepper into small pieces. Stack the spinach leaves, roll them up, and slice them thin.
Stir the diced bell pepper, spinach, and shredded cheddar into the egg mixture.
Evenly distribute the mixture into the greased muffin cups, filling each about ¾ full.
Bake for 20-25 minutes or until the centers are set and no longer runny.
Let cool slightly before serving. Top with avocado before eating.
Notes
Serving Suggestion: Serve warm with extra avocado on top or alongside whole-grain toast.
Storage: Store leftovers in an airtight container in the fridge for up to 5 days or freeze for up to 1 month.
Reheating: Microwave thawed muffins on high for 45-60 seconds until hot.
Protein content: ~ 9 g per muffin