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

In a large skillet over medium heat, add olive oil and diced bacon. Cook until crispy and golden. Remove from the skillet and set aside.

Using the same skillet, add minced garlic. Sauté for about 1 minute until fragrant, taking care not to burn it.

In a bowl, whisk together eggs, heavy cream, grated Parmesan, and season with salt and pepper.

Reduce heat to low, then add cooked pasta back to the skillet. Quickly mix in the bacon, then pour the egg and cream mixture over the pasta, stirring thoroughly to coat.

Gradually add reserved pasta water to achieve a creamy consistency, and keep stirring until the sauce thickens and coats the pasta without scrambling the eggs.

Remove from heat and garnish with freshly chopped parsley and additional Parmesan cheese if desired.