A quick, creamy carbonara made without cream — eggs, cheese, and pasta water create a silky sauce. Earthy mushrooms add savory depth. Ready in about 20 minutes for two people.
Bring a large pot of salted water to a rolling boil and cook the pasta until just shy of al dente — a minute or two less than package time. Reserve about a cup of the pasta cooking water, then drain the pasta.
While the pasta cooks, heat a large skillet over medium heat. Add the diced pancetta (or guanciale) and cook until browned and crisp and the fat has rendered. If using a little olive oil, add it before the pancetta; otherwise the meat will render its own fat. Remove most of the crisped meat to a plate, leaving the fat in the pan.
In the same skillet, add a bit of butter or a splash of oil if the pan is dry, then add the sliced mushrooms. Sauté until they are golden and any released liquid has evaporated. Season lightly with salt and some freshly ground black pepper.
In a bowl, whisk together the egg yolks and most of the grated cheese until smooth. Add a generous amount of freshly ground black pepper. This mixture will create the creamy carbonara sauce.
Return the cooked pasta to the skillet with the mushrooms and toss briefly over low heat. Remove the pan from the heat. Quickly pour the egg and cheese mixture over the hot pasta and toss or stir vigorously, adding reserved pasta water in small splashes as needed to loosen the sauce and reach a silky consistency. Stir in the crisped pancetta. The residual heat will gently cook the yolks without scrambling them.
Taste and adjust seasoning with salt and more black pepper if desired. Serve immediately, topped with the remaining grated cheese and extra black pepper.