Serves 4.
Ingredients
2 tsp olive oil
1 small onion, diced
12 oz pre-cooked Italian sausage (I like Al Fresco "fully cooked" chicken sausage with mozzarella and sun-dried tomato)
1 medium bell pepper (any color), thinly sliced
8 oz sliced mushrooms, cremini or white button mushrooms
8 large eggs
7 oz shredded cheese (I like low-fat 4-cheese Italian blend)
2 tsp milk (nonfat or low-fat)
2 tsp fresh thyme leaves
1/4 tsp kosher salt
1/4 tsp fresh black pepper
1/4 cup grated Parmigiano-Reggiano cheese, or more to taste
Directions
Preheat the broiler.
Heat an oven-safe, nonstick 10-or 11-inch frying pan over low heat, and add the olive oil, onion, sausage and bell pepper. Sauté for 3-4 minutes, until the onion is translucent. Then add the mushrooms, and continue to cook until the sausage is browned and the mushrooms have given off most of their liquid.
In a large glass measuring cup or bowl, quickly whisk together the eggs, shredded cheese and milk. Stir in the thyme, salt and pepper. Pour the egg mixture on top of the vegetables in the pan.
Cover the pan, and cook on low heat for 3 minutes. Using a rubber spatula, gently lift the edge of the frittata here and there, and allow the uncooked egg to run underneath. Cook covered, for 3-4 minutes more, or until the frittata is almost completely set but the top is a little bit runny.
Remove the pan from heat, and sprinkle with the parmesan cheese. Place the pan under the broiler until the cheese is bubbling and melted; how long that takes will depend on the type of broiler you have. (My infrared broiler took only one minute to melt the cheese, so keep an eye on it.)
Remove the pan from the oven, and let it sit for 5 minutes before cutting into wedges. Serve warm or at room temperature.