Method
Preheat the oven to 180°C (350°F) with a rack in the centre. Spray a 12-cup muffin tin generously, or use silicone cups, which release more easily.
Finely chop the spinach, dice the red pepper and thinly slice the green onions.
Divide the spinach, pepper, green onion and crumbled feta evenly between the 12 cups.
Whisk the eggs, egg whites and pepper in a large measuring cup or jug until well combined.
Pour the egg mixture over the vegetables, filling each cup about three-quarters full.
Bake on the centre rack for 20 to 22 minutes, until puffed and set in the centre with no liquid egg, 74°C (165°F) inside.
Cool in the tin for 5 minutes, then run a thin knife around each muffin and lift it out. They sink slightly as they cool; that is normal.
Tips
- Silicone muffin cups release much more easily than metal.
Swaps
- Dairy-free: skip the feta and add a pinch of salt.
Storing and reheating
Keeps 4 days in the fridge or 2 months frozen. Microwave 30 to 45 seconds.