Preparation

• Position a rack in the center of the oven and heat to 350°F.
• In a small bowl, combine the mustard, olive oil, 1/4 tsp. salt, and 1/8 tsp. pepper.
• Trim the bottom of the romanesco so that it sits flat, and remove the tough center core from the stem, leaving the head intact. Place in an 8×8-inch baking dish.
• Brush the mustard mixture over the surface of the romanesco, and sprinkle with the thyme. Add 1 cup of water to the bottom of the baking dish, and bake until tender and the tips are deeply browned, about 1 hour, loosely tenting with aluminum foil about halfway through roasting. Quarter the romanesco, drizzle with extra-virgin olive oil, and serve with sea salt to taste.