Butternut squash makes an awesome thick and luxurious soup. Roast it and puree it with chicken or veggie stock. You can keep it simple by pureeing onion, celery, carrot, potato, and butter with it. If you want it savoury puree it with a bit of turmeric/curry powder, ginger, garlic, cumin, cinnamon, chili powder (if you like it spicy). If you can, toast the cumin whole and ground it first so it can bloom. S&P to taste, of course.