This recipe is part of O's comfort food menu
Meanwhile, cook pasta according to package directions in boiling water with sea salt. While pasta cooks, stir together yolks, parsley, and 1/3 cup of cheese. Return pancetta and onions to medium heat; add cream and pepper and bring to a slow simmer.
Strain pasta, reserving 1 1/4 cups of pasta water. Blend 1/4 cup of pasta water with yolk mixture, then stir into pancetta cream sauce. Add 1/2 to 3/4 cup more of pasta water and simmer sauce until bubbling and slightly thickened, about 1 minute.
Return pasta to pot and toss with sauce. If necessary, add more pasta water to make sauce creamy. Serve with additional grated cheese on the side, if desired.