Over medium-low, heat the oil in a large sauté pan. Add the guanciale (we used ham), stirring, until the fat renders out and the pieces become brown and crisp. Use a slotted spoon to transfer the pieces to a small bowl, leaving the rendered fat in the pan.Meanwhile, while the guanciale is cooking, cook your pasta of choice in a large pot of boiling water, stirring occasionally, until pasta is about halfway cooked, not yet al dente. Save 1.5 cups the pasta water and then drain the pasta.Add 3/4 cups pasta water to the pan with the fat and bring to a gentle boil over medium heat, swirling often to emulsify the pasta water and rendered fat, about 1 minute. Add the pasta to the pan and cook until pasta is cooked al dente and the sauce becomes thick and glossy, about 5-7 minutes.Turn the heat up to medium-high and add back in the crispy guanciale, pepper, and two-thirds of the grated Pecorino. Toss well to melt the cheese and combine. Enjoy immediately topped off with the remaining Pecorino.