Preheat oven to 350 degrees F. Pour ¼ cup water into a square baking dish.
Remove the cauliflower's outer leaves but leave the stem intact, trimming it just a little so that the cauliflower head can stand upright in the pan (as shown in the video).
Wash the cauliflower and dry well with paper towels.
Brush the cauliflower all over with the olive oil, and sprinkle with the seasonings. Spray the seasoned cauliflower with olive oil spray.
Place the cauliflower head, stem side down, in the prepared baking dish. Roast, uncovered, for 40 minutes.
Carefully remove the pan from the oven, placing it on a trivet mat and leaving the oven on. Use two wide spatulas to temporarily transfer the cauliflower to a plate. Wipe the pan clean with paper towels (careful, it will be hot). Pour ¼ cup more hot water into the pan. Make sure water is hot, especially if using a Pyrex pan.
Return the cauliflower to the pan, stem side down. Spray it with more olive oil. Place the pan back in the oven, and continue roasting the cauliflower until the outside is browned and crispy and the inside is tender-crisp, about 40 more minutes.