Cut the hog jowl into small lardons and put into a cold pan. Cook the jowl over medium-high heat until crunchy and almost all of the fat is rendered. Once done, remove from heat and set aside. Keep pan with rendered fat for later on.
In a bowl, mix the egg yolks until you get a smooth cream, add the pecorino and black pepper to the bowl and whisk together until fully smooth and creamy (make sure there are no lumps).
Bring a pot of water to a boil and cook the spaghetti according to the instructions on the packaging (usually a minute or two less for al dente). Pecorino cheese is quite salty, so keep that in mind when salting the water. Once the pasta is cooked, drain and add the spaghetti to the pan where you previously cooked the hog jowl.
Mix the spaghetti and jowl together (off the heat) and slowly add the mixture of egg yolks, pecorino and black pepper and mix until the spaghetti is evenly coated. Serve immediately and enjoy!