1. Cook the Barilla® pasta for half the time indicated on the package. Drain pasta and drizzle with some olive oil to prevent from sticking. Place pasta flat on sheet trays or hotel pans and cool in a blast chiller. Alternatively, cool it down in a walk-in cooler. Store in zip lock bags or sealed plastic container; refrigerate and use within several hours.
2. Heat the oil in a large pan and caramelize the onions slowly over medium-low heat until melting. Set aside.
3. For each serving, to order: Warm some of the caramelized onions in a pan. Add about 2 1/2 Tbsp bacon and render it, then toss in 1/3 cup Brussel sprout leaves and cook until wilted, about 2 minutes.
4. Reheat about 1 1/3 cups pasta in simmering water. Drain and add it to the onion mixture with some cooking water to thicken the sauce. Stir in 1 Tbsp Romano, 1/2 tsp butter, and salt and pepper to taste. Plate the pasta.
