Bring a high-sided pan filled with water to a boil. Season liberally with salt. Place the bucatini in the water.
Heat the olive oil over medium heat in a large saute pan, then add the pancetta. Cook until the pancetta has rendered and the meat is caramelized, about 3 minutes. Add the garlic and about 1 tablespoon black pepper to the pan to toast, about 1 minute. Add a ladle of pasta water to stop the cooking process and let simmer on low heat, 2 to 3 minutes.
Meanwhile, whisk together the eggs and egg yolk in a bowl. Add the Parmesan and Pecorino-Romano and whisk to combine. Slowly add a ladle of the pasta water to temper the eggs. Set aside. When the pasta is al dente, add the pasta to the pancetta pan straight from the water. Remove from the heat and add freshly cracked pepper to taste. Add the egg mixture and toss gently to coat. If the sauce gets too thick, add some additional pasta water. Garnish with a generous sprinkling of Pecorino-Romano and a drizzle of olive oil.