Heat the oven to 350 degrees.
Soak the clay pot (bottom and top) in cool water.
Prepare the vegetables.
Microwave the chopped onion with the oil in a microwave-proof dish on HIGH (100 percent) for 3 to 4 minutes, or just until the onions begin to soften.
Pour the water out of the clay pot. Place the cauliflower florets in the bottom of the clay pot. Sprinkle with half of the herbs.
Layer on top of the cauliflower, the cooked onions (with their juice), the chopped red bell pepper, and the chopped tomatoes.
Pour the cup of wine over the vegetables and sprinkle with the remaining herbs.
Cover and bake until the cauliflower is tender but still has a bit of resistance to the tooth. Check after 1 hour. Depending on the size of your pot, it could take 1.25 to 1.5 hours.
Meanwhile, prepare the linguine according to the package directions.
Lightly toss the cauliflower mixture to distribute the ingredients. If desired, though not necessary, season lightly with salt and freshly ground black pepper. Serve on top of the hot linguine.
