Bring a large pot of salted water to a boil. Add spaghetti and cook according to package instructions until al dente or desired tenderness. Reserve 1 cup of pasta water and drain the rest.
Cook the pancetta In a large skillet over medium heat, cook the pancetta or bacon until crispy. Add minced garlic and cook for 1 minute until fragrant. Mix eggs and cheese In a bowl, whisk together eggs and grated Parmesan until smooth. Combine pasta and pancetta Add cooked spaghetti to the skillet with pancetta. Remove from heat. Slowly pour the egg-cheese mixture over the pasta, tossing quickly to create a creamy sauce. Add reserved pasta water a little at a time if needed to reach the desired consistency. Season and serveSeason generously with freshly ground black pepper and a pinch of salt if needed. Remove from heat and drizzle in the extra-virgin olive oil.
Garnish with chopped parsley and extra Parmesan if desired. Serve immediately.