Sprinkle the cauliflower generously with salt and pepper.Roast the cauliflower on the middle rack for 20 to 30 minutes or until it is tender.Combine the roasted cauliflower, goat cheese, Parmesan cheese, heavy cream, sour cream, butter, chives, parsley, dill, garlic, and red pepper flakes, if using, into a food processor.Pulse until smooth and fluffy.