Start by bringing a large pot of salted water to a vigorous boil. Cook the spaghetti according to the package instructions until al dente. Before draining, reserve 1/2 cup of the pasta water, then set the spaghetti aside.

In a small mixing bowl, whisk together the eggs and freshly grated Parmesan cheese until well combined. Set this mixture aside for later.

In a large cast iron skillet over medium-high heat, cook the diced bacon until it becomes golden and crispy, which should take about 6-8 minutes. Be sure to keep some of the rendered fat in the skillet for added flavor.

Add the minced garlic to the skillet and sauté for about a minute, just until it becomes aromatic. Lower the heat to a gentle simmer.

Quickly add the drained pasta to the skillet along with the egg and Parmesan mixture. Toss everything together gently to ensure the pasta is thoroughly coated. Season with kosher salt and freshly ground black pepper to taste. If needed, gradually stir in the reserved pasta water, a tablespoon at a time, until you reach your preferred sauce consistency.

Serve the pasta immediately, garnished with freshly chopped parsley if you like.