Ingredients
- Olive oil
- ¾ cup chopped onion
- 2 garlic cloves, minced
- ¾ cup thinly sliced red bell pepper
- 1½ cups sliced mushrooms
- 1½ cups thick-cut julienned zucchini
- 1 teaspoon dried oregano
- Salt and freshly ground black pepper to taste
- 9 extra-large eggs
- ½ cup whole milk
- 1½ cups (6 ounces) shredded sharp white Cheddar cheese
- ½ cup grated Parmesan cheese, plus more for serving
- 2 (8-ounce) packages cream cheese, softened and pulled into bite-size pieces
- 3 cups leftover cooked spaghetti
How to Make It
- Preheat the oven to 350°.
- In a Lodge 10-inch cast iron skillet, heat just enough oil to coat the bottom of the pan over medium heat. Add the onion and garlic, and cook, stirring a few times, until the onion is softened, about 5 minutes. Add the bell pepper, mushrooms, and zucchini, and cook, stirring a few times, until softened, 6 to 10 minutes. Add the oregano, and season with salt and pepper to taste; transfer the mixture to a bowl. (If the vegetables have given off a lot of liquid, drain off most of it.) Wipe out the skillet, and brush lightly with oil. Cut a piece of parchment to size, and place in the bottom of the pan. Brush with oil. Set aside.
- In large bowl, using an electric mixer on low speed, beat the eggs, milk, 1½ teaspoons salt, and 1 teaspoon pepper. Add the Cheddar and Parmesan, and blend on low. With the mixer running, add the cream cheese, a few pieces at a time, beating until blended.
- Put the spaghetti in the prepared skillet. Spoon in the vegetables. Pour in the egg mixture. Mix with your hands so that all the components are equally distributed within the pan. Pat down so that as much as possible of the solids are covered with liquid. Bake until firm to the touch and lightly browned, 30 to 40 minutes. It will puff up when baking, then settle as it cools.
- Cut into wedges, and serve immediately sprinkled with some freshly grated Parmesan. This is also good served the next day. Wait until the frittata is cool, invert it onto a plate, remove parchment, and turn right-side up. Refrigerate and, when cold, cut into portions. Wrap them well, and refrigerate. The next day, unwrap the wedges, place on a baking sheet lined with parchment paper, and reheat for 10 to 15 minutes at 400°.