How to Make It
Cook the spaghetti according to the package directions. Drain and return it to the pot.
Preheat oven to 425° F. Toss the spaghetti with 2 cups of the marinara sauce, the eggs, and ½ cup of the mozzarella. Season with ½ teaspoon each salt and pepper.
Heat 1 teaspoon of the oil in a 10-inch ovenproof skillet over medium-high heat. Add the spaghetti mixture and gently press it down. Top with the remaining 1 cup of marinara and ½ cup of mozzarella, then the pepperoni. Bake until browned, 18 to 20 minutes.
Meanwhile, in a large bowl, whisk together the remaining 2 tablespoons of oil, the vinegar, ½ teaspoon salt, and ¼ teaspoon pepper. Add the greens and toss to combine. Serve with the pizza.