Bring a pasta pot of salted water to a boil. Add the pasta to the water and cook to al dente.

While the pasta is cooking, pre-heat a large skillet over medium-high heat. Add the olive oil and cook the pancetta or bacon until the fat has been rendered out and the pancetta or bacon is almost crispy – about 6 to 8 minutes. Drain off all but about 3 tablespoons of bacon fat and remove the pan from the heat.

Beat the eggs with the cheeses in a large bowl.

Just before the pasta is al dente, remove a cup of the hot pasta water from the pot. Whisk ½ cup of this hot liquid into the egg and cheese mixture, reserving the remaining ½ cup of pasta water.

Drain the pasta and immediately transfer the pasta to the skillet with the bacon. Toss to coat all the pasta with the bacon fat. Stirring constantly, pour the egg and cheese mixture into the hot pasta. Stir well and add the parsley and the freshly ground black pepper. Use the residual pasta water to thin the pasta sauce to the desired consistency and serve immediately.