2 cups grated Pecorino Romano, plus more for serving
1 1/2 cups reserved pasta-cooking water
Bring a large pot of salted water to a boil for pasta. Cook according to package instructions, reserving 1 1/2 cups of hot pasta cooking water.
While pasta cooks, heat olive oil on a medium-low setting in a large saucepan. Cook pancetta with garlic until pancetta begins to brown and crisp, about 10-15 min. stirring often. Remove and discard garlic once it begins to soften, before pancetta is done cooking. Season with black pepper.
Add 1 cup of the pasta cooking water to the saucepan with pancetta. Turn up the heat to high and cook for about 1 min. to create a thick, glossy sauce.
Toss hot pasta in the pan with sauce to coat. Stir in cheese until melted and combined. Add more pasta cooking water as to create a loose sauce.