Whisk together eggs yolks, Parmesan and pepper; set aside.
Heat oil in large skillet set over medium-high heat; cook pancetta for 5 to 7 minutes. Stir in cauliflower; cook for about 5 minutes. Stir in green onions and garlic; cook for about 5 minutes.
Cook macaroni according to package directions. Drain and reserve 1/3 cup (75 mL) cooking liquid. Stir hot macaroni into cauliflower mixture until well coated. Remove from heat.
Stir reserved egg yolk mixture into skillet until thickened, adding reserved cooking liquid.
It’s important to work quickly when preparing this recipe to ensure the sauce thickens, but that the eggs don’t scramble; as long as the pasta is hot and the pan is off the heat, the sauce will be perfect.Cauliflower can be replaced with broccoli, mushrooms, grape tomatoes or chopped zucchini if desired.