01 -
Preheat oven to 350°F (175°C) and lightly grease a muffin tin with olive oil spray or use silicone liners.
02 -
Dice the cherry tomatoes, bell peppers, and green onions. Chop the spinach.
03 -
Divide the chopped vegetables evenly among the muffin cups, filling them halfway.
04 -
Sprinkle a little shredded cheese in each cup if using.
05 -
Pour egg whites over the veggies in each cup, filling almost to the top.
06 -
Sprinkle salt and black pepper over each filled cup.
07 -
Bake for 20–25 minutes or until the egg whites are set and tops are lightly golden.
08 -
Remove from oven and let cool for 5 minutes before removing from the tin. Serve warm or allow to cool completely before storing.