2-3 strips bacon
Boil water for pasta. Add salt. Coarsely chop the bacon. When the water is boiling, add pasta. Then put the bacon in a frying pan over medium-low heat. As those are in process, grate a handful or two of good parmesan into a bowl. Crack an egg or two into the bowl, and beat with a fork. Add a hefty amount of freshly ground pepper. When the pasta is cooked, drain it and dump in the bowl, tossing it like mad to coat it evenly with egg. The bacon should be nice and crispy at this point, so fold it in as well - though you probably wanna use a slotted spoon or some such device to remove it from the pan, because otherwise your pasta will be ridiculously greasy.
Ideally, the final result is a somewhat gooey and creamy pasta, with the egg partly cooked and the parmesan partly melted, accentuated by the ground pepper and crispy bacon.
All in all, it takes less than 10 minutes to make, and is pretty basic. A lot of carbonara recipes involve cream, but I find that it becomes much too heavy that way - the cheese, egg and bacon is already pretty rich. All the same, it's a fairly simple dish, and I'm still trying to think of ways to spice it up a bit. Please to leave comments with any ideas.