For me, high-heat roasting is about the biggest favor you can do for a head of cauliflower. And the best way to pull it off is to slice the head into "steaks." First, trim off all the green leaves and stalks from the base of the cauliflower. Then, with the stem facing straight up, slice down along the right side of the stem, cutting off the right "lobe." Next, slice straight down the middle of the stem, which will give you your first flat-cut steak, about an inch thick. Slice down the left side of the stem to get your second flat-cut steak, and your left lobe.
Preheat your oven to 450°, with an oven-proof pan (cast-iron works best) inside while it preheats. Brush the cauliflower pieces with olive oil, and season with salt and pepper. Roast them at 450° for 12 minutes or until well-browned on the bottom. Turn the cauliflower, and roast for an additional 8 minutes or until cauliflower is well-browned and tender (the thicker lobe pieces may need a few extra minutes on their own).
This method gives cauliflower a delectable, crisp, meaty-flavored exterior crust and tender, practically creamy flesh within. It turns cauliflower into the star of the plate, which is how I like to use it: as the main attraction in a light vegetarian meal. Dress it with a little herby vinaigrette, or some chopped parsley and shallot with capers. You can also use it as an impressive platform for plating your meats.