Cook spaghetti according to package directions for al dente. Meanwhile, in a large bowl, whisk eggs and Parmesan; set aside. , In a large skillet, heat oil over medium heat. Add pancetta; cook and stir until crispy, 5-6 minutes. Add garlic; cook 1 minute longer. , Drain spaghetti, reserving 3/4 cup pasta water. Add spaghetti to skillet; toss to coat. Slowly add egg mixture, stirring constantly. Add salt, pepper and enough pasta water for sauce to reach desired consistency. Sprinkle with parsley, and additional Parmesan if desired.