1. Set a large, rimmed baking pan on the middle shelf of the oven; preheat to 500 degrees F. Bring a large pot of water to a boil; add salt. Put cauliflower, onions, carrots, and squash in the pot; cover until water returns to a boil. Uncover; cook 2 minutes. With a slotted spoon, transfer vegetables to a colander. Reserve cooking water for later.
2. In a bowl, toss vegetables, shrimp, tomatoes, wine, oil, garlic, cumin, red pepper, and thyme. Transfer to the pan in the oven; roast 15 minutes, stirring midway, until veggies are tender and shrimp is cooked. Discard thyme.
3. Return the pot of water to a boil. Add pasta and cook until al dente. Drain and transfer to a wide serving bowl. Toss pasta with veggie mixture; season with salt and pepper. Add cheese if desired.