Boil the spaghetti in ≈ 4000 g Water for the pasta with 30 g Salt for the water until 2 minutes short of al dente. Reserve 100 ml reserved pasta water.

Render 150 g Guanciale in a cold pan brought slowly to medium heat.

Whisk ≈ 100 g Egg yolks with 100 g Pecorino Romano and 3 g Black pepper to a thick paste.

Off the heat, toss the pasta with the fat, then the egg paste, loosening with 50 ml reserved pasta water (half) until glossy.