Heat the remaining 1 tablespoon olive oil in the skillet over medium-high heat. Add the cauliflower and cook until the edges brown, about 4 minutes. Add the red pepper flakes and toast 30 seconds. Add the reserved pasta water and cook until the liquid is reduced by half and the cauliflower is crisp-tender, about 1 more minute.
04Add the pasta, onion mixture and parmesan to the skillet and toss. Season with salt. Top with the basil, pine nuts and more parmesan. Photograph by Andrew Mccaul