Preheat your oven to 375°F (190°C). Cut the bottom of the cauliflower off, leaving a little stub for it to sit on, and remove most of the bottom leaves.
Place your cauliflower in a baking pan or a Dutch / French oven with a lid that will close over it. I use a Staub cast iron cooking vessel with a glass lid but you can use a baking pan and cover with foil.
Fill your cooking vessel with a little water (just enough to cover the bottom) and drizzle the cauliflower with a little olive oil and sprinkle with salt and pepper. Cook, covered, for 40 minutes.
After 40 minutes, remove the lid, drizzle with a little more oil, add a sprinkle of Aleppo pepper if you'd like, and then place back in the oven at 425°F (220°C) for another 40 minutes uncovered, until it's golden brown all over and the top is beginning to char just a little. Remove from the oven and set aside.