Bring a large pot of salted water to a boil and cook bucatini according to package instructions until al dente. Reserve 1/2 cup pasta water before draining.
While pasta cooks, heat a large skillet over medium heat. Add pancetta and cook until crisp, about 5–7 minutes. Remove from heat.
In a mixing bowl, whisk together eggs, Pecorino Romano, and plenty of black pepper until smooth.
Add the hot pasta to the skillet with pancetta and toss to coat.
Quickly pour the egg mixture over the pasta, tossing constantly to create a creamy sauce. Add reserved pasta water as needed to reach desired consistency.
Serve immediately with extra Pecorino Romano and black pepper on top.