Bring a large pot of salted water to a rolling boil. Add the spaghetti and cook until al dente, following package instructions. Reserve ½ cup of pasta water before draining.

In a skillet over medium heat, add diced pancetta or guanciale. Cook until crispy and golden brown, about 5-7 minutes. Remove from heat and set aside.

In a mixing bowl, whisk together the eggs and grated Parmesan cheese. Add freshly cracked black pepper.

Once the pasta is drained, add it to the skillet with the crispy pancetta. Toss to combine.

Pour the egg and cheese mixture over the hot pasta, tossing continuously until sauce thickens. Add a splash of reserved pasta water if too thick.

Taste and adjust salt if needed. Serve immediately while warm and creamy, garnished with extra Parmesan if desired.