Bring a large pot of salted water to a boil. Add the spaghetti and cook according to the package instructions until al dente. Reserve about 1 cup of pasta water, then drain the pasta.

While the pasta is cooking, heat a large skillet over medium heat. Add the diced bacon and cook until crispy, about 5-7 minutes. Remove the bacon with a slotted spoon and set aside, leaving the bacon fat in the skillet.

In a medium bowl, whisk together the eggs, grated Parmesan cheese, Pecorino Romano (if using), and a generous amount of freshly ground black pepper.

Add the minced garlic to the skillet with the bacon fat and sauté for about 1 minute until fragrant.

Add the cooked pasta to the skillet and toss to coat in the bacon fat and garlic.

Remove the skillet from the heat and quickly pour the egg and cheese mixture over the pasta, tossing vigorously to coat the pasta evenly. The heat from the pasta will cook the eggs, creating a creamy sauce. If the sauce is too thick, add some reserved pasta water, a little at a time, until you reach the desired consistency.

Stir in the cooked bacon.

Taste and season with additional salt and pepper if needed.

Garnish with chopped fresh parsley and additional grated cheese if desired.

Serve the Carbonara hot, and enjoy this classic Italian dish with a side of garlic bread or a fresh green salad.