Put the quinoa and filtered water in a glass bowl and set aside to soak while you are prepping the vegetables.
Peel the squash, cut it in half, remove the seeds and strings, and cut into a ½-inch dice. Add to a large mixing bowl, along with the carrots, celery, kale, black beans, if using, and garlic.
Drizzle the oil over the vegetables and toss. Sprinkle with the curry powder and toss until evenly coated. Set aside.
Preheat the oven to 400°F (200°C). Spray or oil a large lidded casserole dish. If you don’t have a lid, cut a piece of aluminum foil to cover. Set aside.
Drain and rinse the quinoa.
Add the drained quinoa and stock to the casserole dish. Gently agitate the dish to distribute the quinoa evenly, while keeping it submerged in the liquid.
Carefully add the vegetables evenly on top, spreading with a spatula and keeping as much of the quinoa in contact with the liquid as possible.
Bake, covered or wrapped tightly in foil, for 35 to 45 minutes, or just until the vegetables are fork-tender.
Remove from the oven, uncover, and let rest for a few minutes before serving.