Fill a large pot with water, add salt at a ratio of 1 tablespoon per 2 quarts, and bring it to a boil.

While waiting for the water to boil, warm the olive oil or butter in a large sauté pan over medium heat. Add the diced pancetta or bacon and cook slowly until it becomes crisp. If using garlic, stir it in and cook for another minute. Then, turn off the heat and transfer the pancetta and garlic to a large mixing bowl.

In a separate small bowl, beat the eggs and stir in about half of the grated cheese.

Once the water reaches a rolling boil, add your pasta of choice and cook uncovered until it’s al dente.

When the pasta is done—tender but still firm—use tongs to transfer it directly from the pot into the bowl with the pancetta and garlic. Don’t worry about excess water; the pasta should be dripping wet. Set aside some of the pasta cooking water to use later if needed.

Quickly toss the hot pasta with the pancetta mixture to begin forming the sauce. Let it sit briefly to avoid scrambling the eggs when added. The residual heat from the pasta is what gently cooks the eggs to create a smooth, creamy sauce.

Pour in the egg and cheese mixture and toss everything vigorously to combine. Season with salt to taste. Add a splash of the reserved pasta water if the mixture seems dry, ensuring a silky consistency.