Bring a large pot of water to a boil. Add pasta and cook until al dente, tender but firm, according to the package directions.
In the meanwhile, heat olive oil in a medium saute pan over medium heat and add bacon. Saute until browned and slightly crisp, 3-5 minutes. Pour off all but 1 tablespoon of fat. Toss garlic into pan and saute for less than a minute, until fragrant. Add red bell peppers and mushrooms and saute until slightly softened, about 3 minutes.
In a small bowl, beat eggs with a fork to loosen them. Add nutmeg and parmesan, stirring together to prevent lumps.
Strain pasta, reserving 1/4 cup of pasta cooking water for use later. If pan with bacon and vegetables has cooled down, warm it up again and add pasta. Using tongs, toss pasta. Turn off heat (to avoid scrambling the eggs) and, working quickly, add egg mixture to pasta and toss thoroughly. If sauce seems too dry, add one tablespoon of reserved pasta cooking water at a time until you reach desired consistency and toss again. Sprinkle with parsley. Serve with grated cheese and coarsely ground pepper.
Calories: 370kcal | Carbohydrates: 24g | Protein: 23g | Fat: 24g | Saturated Fat: 9g | Sodium: 490mg | Sugar: 1g