1. Cook the pasta according to the package directions, reserving 1/2 cup of the cooking water. Drain the pasta and return it to the pot.
2. Meanwhile, brown the pancetta or bacon in a large skillet over medium heat, tossing occasionally, until crisp, 8-10 minutes; transfer to a plate.
3. Add the oil, cauliflower, 1/2 cup water, 3/4 tsp salt, and 1/2 tsp pepper to the drippings in the skillet. Increase heat to medium-high and cook, covered, until the water has evaporated and the cauliflower is almost tender, 4-5 minutes. Uncover and cook, tossing occasionally, until golden brown and tender, 4-6 minutes more.
4. Add the cauliflower, egg, egg yolks, Parmesan, and 1/4 cup of the reserved cooking water to the pasta and toss to coat (adding more cooking water as needed to loosen the sauce). Top with additional black pepper.