½ cupfinely diced red bell pepper(½ of a red pepper)
½ cupfinely diced yellow onion(½ of a small onion)
3cupsloosely packed spinach, roughly chopped
4largeeggs
4egg whites(see note)
¼ cupskim milk(nonfat, 2%, or whole milk is fine)
⅔ cupshredded sharp cheddar cheese
salt and pepper to taste
Instructions
Preheat oven to 375°F. Generously grease or spray a muffin tin with 12 wells. It's important to grease the tins well because the frittatas tend to stick a bit.
In a medium skillet, heat the oil over medium high heat. When hot, add peppers and onions and sauté until softened, about five minutes, stirring occasionally. Add spinach and stir gently until wilted. Remove from heat.
Meanwhile, in a large bowl, whisk together eggs, egg whites, skim milk, cheese, salt and pepper.
Pour egg mixture into prepared muffin tin so that each one is about one half to two thirds full. Add sautéed vegetables, divided evenly, to each well.
Bake for 20 to 25 minutes or until puffed and golden brown. Cool in muffin tin for about 5 minutes; remove and serve.
Notes
2 whole eggs can be substituted for the 4 egg whites (use 6 eggs total).
If desired, add ½ cup finely diced ham or crumbled bacon.
Make Ahead: Baked frittatas can be refrigerated for up to 5 days or frozen for up to 3 months. Microwave to reheat, either frozen or thawed. I like to wrap them in a damp paper towel before microwaving them so they don't dry out.