Stack the Pancetta (6 ounce) and using a very sharp knife, cut the stack into a 1/4 inch dice.
Heat a large, heavy-bottomed pan over medium heat and add the Olive Oil (1 tablespoon). When the oil is hot, add the pancetta and cook for 8 to 10 minutes, stirring occasional until lightly golden.
Then add the Garlic (4 clove), stirring constantly, cooking for 1 more minute. Turn off the heat and set aside. Do not pour off the fat, as it adds to the flavor and texture of the dish.
Beat the large Egg (3) in a bowl, adding the Kosher Salt (1/2 teaspoon), Ground Black Pepper (1/4 teaspoon), and Pecorino Romano Cheese (1 cup). Whisk until incorporated. Set the bowl aside to allow the eggs to come to room temperature.
Bring a large pot of generously salted water to a boil. Add the dried Spaghetti (1 pound), and cook 7 -9 minutes, or until al dente. Before you drain the pasta, reserve 1/2 cup of pasta water.
Add the drained pasta to the pan with the pancetta. Toss until well mixed. Add the egg mixture and 1/4 cup of the reserved pasta water, and quickly toss to coat the pasta. Toss quickly and constantly so the egg creates a creamy sauce.
If using, add a pinch of Ground Nutmeg (1 pinch) and toss to combine.
Garnish the dish with extra Pecorino and Fresh Parsley (1 handful). Serve immediately.