heat oil in a large skillet over medium-low.

cook pancetta, stirring often, until it starts to brown and crisp, 10–15 minutes;

remove to a plate

cook pasta in a large pot of boiling lightly salted water, stirring occasionally, until pasta is about halfway cooked (not quite al dente); drain, reserving 1 ½ cups pasta cooking liquid.

add ¾ cup pasta cooking liquid to reserved skillet and bring to a gentle boil over medium heat, swirling often to encourage drippings and liquid to emulsify, about 1 minute.

add pasta and cook, tossing often and adding more pasta cooking liquid as needed, until pasta is al dente and a thick, glossy sauce forms, 5–7 minutes (this second cooking is why you undercook the pasta initially).

increase heat to medium-high. add pancetta, pepper, and two-thirds of cheese; toss well to combine and melt cheese.

serve pasta topped with remaining cheese