1. With a rack set at position “2,” select Gourmet Mode and choose Vegetable and then Roasted. Let the oven preheat.
2. Trim and remove leaves at the bottom of the cauliflower head. Carefully cut off and remove the stem and tough core, keeping the head intact. Rinse and pat dry the trimmed cauliflower head.
3. Drizzle cauliflower with olive oil. With your hands, rub oil all over, on top and bottom, until the cauliflower is well coated. Season both sides of the cauliflower liberally with salt.
4. Place cauliflower florets side up in a cast iron skillet. Cover tightly with aluminum foil. Place skillet in oven. Cook for 30 minutes, covered.
5. Remove foil and roast uncovered for an additional hour. Once the cauliflower is golden brown on the outside and tender on the inside, remove from oven. A knife should slide in and out without any resistance.
6. Transfer the cauliflower head to a platter. Carve and serve as-is, or drizzle with your favorite dipping sauce or fresh herbs.