Roasting cauliflower this way makes a great presentation. And it is delicious! Serve as a side dish or the main course.
Preheat the oven to 375F. Rinse head of cauliflower and remove any green leaves from the bottom. Cut off the edge of the stem at the bottom so that the cauliflower will sit flat on the baking dish. Heat the oil in a skillet on medium high heat. Add the garlic and saute for about a minute. Add in the vegetable stock and wine, and bring to a boil. Mix the flour in a small bowl with about 2 tablespoons of water and whisk until smooth. Whisk the flour mixture into the skillet and lower heat to a simmer. Add in the dijon mustard and stir together. Place the head of cauliflower upside down in a baking dish. Pour about half of the mustard sauce over the bottom of the cauliflower; then carefully flip the cauliflower right side up and pour the rest of the sauce over the cauliflower, coating completely. Sprinkle with the Old Bay Seasoning and season with salt, pepper and thyme. Cover loosely with foil. Place in the oven for an hour and 15 minutes, checking after about 1/2 hour to baste the sauce from the baking dish over the cauliflower. Remove foil and place back in the oven. After about a half hour, baste the cauliflower again, and put back in the oven for another 15 minutes. Depending on the size of the cauliflower you have, it might take more or less time. Turn the heat up to 450F for the last 10 minutes if it needs to brown a little more. Cauliflower is done when a skewer or knife easily pierces the core.