Preheat the oven to 400°F (200°C).
Cut the acorn squash in half from stem to tip. Scoop out the seeds and discard or save for roasting.
Brush the cut sides of the squash with olive oil and season with salt and pepper. Place cut-side down on a baking sheet and roast for 30 minutes.
While the squash is roasting, rinse the wild rice and combine it with 3 cups of water or broth in a saucepan. Bring to a boil, then reduce heat and simmer for about 45 minutes, or until the rice is tender and has split open.
In a large skillet, heat olive oil over medium heat. Add onion and celery, cooking until softened, about 5 minutes.
Add minced garlic and cook for another minute.
Stir in the cooked wild rice, chopped pecans, dried cranberries, thyme, and sage. Season with salt and pepper to taste.
Remove the squash from the oven and flip them cut-side up. If desired, brush the insides with maple syrup.
Fill each squash half generously with the wild rice mixture.
If using, sprinkle feta cheese on top of the stuffing.
Return the stuffed squash to the oven and bake for an additional 15-20 minutes, until the squash is fully tender and the stuffing is heated through.
Serve hot and enjoy!