Guanciale: about 1 oz per person. Substitution: pancetta (unsmoked) but NOT smoked bacon or other smoked pork
Fresh backyard eggs, 1 per person
Parmigianno reggiano and pecorino romano, freshly grated or shredded (some people only use pecorino), about 1oz per person
Spaghetti: 2-3 oz per person (can use whole wheat pasta)
Black pepper, freshly cracked
Start pasta pot heating (4 quarts water or more)
Heat a TB of olive oil in a saute pan.
Slice guanciale into very thin "julienne" slices, add to hot pan.
Cook guanciale slowly over medium heat until lightly crisp and fat rendered. Remove from heat. (If you really prefer, you can drain all but a TB of fat from the pan at this point. If you do, use boiling water to temper the eggs later.)
Separate eggs: all whites can go into a medium bowl together. Each yolk should go into a separate small bowl and reserve.
Add parmigianno/pecorino to the eggwhites and mix well.
When the water boils, add sea salt (I use about 1TB per serving of pasta) and return to a rolling boil. Add pasta to the boiling water and set a timer for 1 minute less than the package directions.
Just before the pasta is ready, temper the egg whites with some of the hot fat from the cooked guanciale (or boiling water). Then add the tempered egg white mix into the pan with the guanciale and mix well.
Check the pasta by removing a piece, bite it in half, and look for any white in the center. If there's still a bit of white in the center, return to boil for another minute. As soon as it's uniform, immediately drain (but DON'T rinse) the pasta and add it to the pan with the guanciale and eggs. Mix well and grind black pepper over it (that's how it gets its name - carbonara refers to the black pepper looking like bits of coal.)
Serve in individual bowls, making a little "well" in the pasta. Add the reserved raw yolk, so each person can mix it in for themselves.
Provide extra cheese and black pepper.
Serve with a nice crisp dry white wine (preferably from central Italy, such as Frascati or Orvieto).