The Italian recipe police get loud whenever someone puts cream in a carbonara - and they are right. A real carbonara is eggs, Pecorino Romano, guanciale, and black pepper. That is it. The famous silky sauce is not cream at all - it is egg yolks gently warmed by the residual heat of just-drained pasta until they turn into a glossy, golden coating.
This walkthrough comes from Chef Jean-Pierre, a classically trained French chef who has been cooking and teaching for 40 years. He learned this recipe from his Italian mother and walks through it the traditional Roman way, no shortcuts and no dairy cream.
The two things that go wrong with carbonara. First is scrambled eggs. The egg mixture has to hit the pasta off the heat (or on very low heat) and get tossed constantly. Drop it on a hot pan and you have an omelet with spaghetti in it. Second is dry, gluey sauce. The starchy pasta water is the fix - splash some in while tossing and the sauce loosens into the silky cream you are after.
Substitutions. If you cannot find guanciale (cured pork jowl), pancetta is the next best swap. Regular bacon works in a pinch but it is smoked, which changes the flavor. Pecorino Romano is non-negotiable for the salty, sharp finish - do not swap in pre-shredded mozzarella or generic parmesan. Use freshly grated cheese, not the pre-shredded stuff with anti-caking powder; the powder fights the sauce.
This recipe takes about 30 minutes start to finish and serves four. While you are here, also worth knowing: how to cook pasta properly, how to make marinara sauce, and how to make meatballs for a full pasta night spread.