Preheat the oven to 400°. Cut pumpkin in half and scrape out the seeds. NOTE: roast the seeds sprinkled with a little salt and/or cinnamon and pepper while the pumpkin halves are roasting. Place pumpkin halves, cut side down on a baking sheet. Cut cauliflower in slices. If using butternut squash, peel and cut into cubes. Drizzle cauliflower (or squash) with olive oil and season with salt and pepper. Spread evenly on a roasting pan and roast the pumpkin and cauliflower for 30 to 40 minutes or until tender when pierced with a fork; be careful not to overcook them.
Remove cooked pumpkin from the skin, discarding skins. Heat Korma curry paste in a medium pot over medium-high heat, and stir. Add coconut milk and cook, stirring occasionally, about 3 minutes. Add 1/3 of the roasted vegetables to the sauce. Serve over rice and place remaining roasted vegetables on top. Serve with fresh chopped cilantro, rice, and/or raita.