By creating a sauce from just broccoli, onions, olive oil and starchy pasta water, this recipe feels Italian in spirit but embraces an unexpected technique. Pulverize onion, broccoli and garlic in a food processor, then cook it in hot oil, much like sofrito, extracting as much flavor as possible. Add stock, orecchiette and broccoli florets, then watch the mixture go from soup, to stew, to saucy pasta. For best results, stick to the ingredients, measurements and temperatures listed in the recipe: Use a different pasta shape, and it will likely overcook; increase the amount of orecchiette, and there won’t be enough liquid; increase the heat and the liquid will evaporate before the pasta cooks through. But with attention, this recipe will yield a glossy pasta that makes cheap, accessible ingredients taste positively lush.