Prepare the Acorn Squashes: Preheat the oven to 400°F (200°C). Cut the acorn squashes in half lengthwise and scoop out the seeds. Place the squash halves cut side down on a baking sheet lined with parchment paper.
Cook the Acorn Squashes: Roast them for 30-40 minutes until tender and caramelized on the edges. Set aside.
Cook the Quinoa: While the squash is roasting, cook the quinoa. In a medium pot, combine the quinoa and vegetable broth or water. Bring to a boil, then reduce the heat to low, cover, and simmer for about 15 minutes, or until the liquid is absorbed and the quinoa is fluffy. Remove from heat and fluff with a fork.
Prepare the Stuffing: In a large skillet over medium heat, sauté the diced onion, garlic, and celery in a water or vegetable broth (no oil needed) for 5-7 minutes until softened. Add the diced apple, cranberries, and spices (nutmeg, thyme, pepper, and salt). Cook for another 3-4 minutes until the apples are tender. Stir in the cooked quinoa, chickpeas, and chopped nuts. Mix everything together thoroughly. Taste and adjust seasonings as needed.
Assemble the Stuffed Squash: Flip the roasted acorn squash halves so the cut side faces up. Spoon the quinoa-chickpea stuffing mixture into each squash half, packing it in generously.
Bake the Stuffed Squash: Place the stuffed squashes back into the oven and bake for another 10-15 minutes to allow the flavors to meld.
Serve: Remove the casserole from the oven and garnish with freshly chopped parsley and vegan parmesan*, if desired. Serve warm.