Bring a large pot of salted water to a boil, then cook spaghetti until al dente, about 8-10 minutes. Reserve 1 cup of pasta water, then drain and set aside.

In a skillet, heat olive oil over medium heat. Add diced pancetta; cook for 4-5 minutes until crispy. Transfer to a paper towel-lined plate.

In the same skillet, add shrimp in a single layer. Cook for 2 minutes each side until pink and opaque. Add minced garlic in the last minute.

In a mixing bowl, whisk egg yolks, grated Parmesan, heavy cream (if using), and black pepper until smooth.

Remove skillet from heat. Add drained spaghetti, then pour egg mixture over pasta. Toss to combine, using reserved pasta water for consistency.

Fold crispy pancetta back into the pasta. Adjust seasoning and serve with fresh parsley on top.