Generally there's NO need to add water while cooking cauliflower for Gobhi Gosht. The cauliflower will release some moisture during the cooking process, and it will cook in its own juices along with the spices and meat. If you're following the recipe mentioned earlier, you add the cauliflower florets to the dish after the meat is cooked, and they will cook in the remaining moisture and flavors of the curry. However, if you find that the dish is drying out or the cauliflower is not cooking properly, you can add a small amount of water, to create some steam and help in the cooking process. Just be cautious not to add too much water, as the dish should have a thick and flavorful gravy.