Prep the squash
Preheat oven to 400ºF (200ºC). Cut the squash in half lengthwise. Remove the seeds with a spoon and discard.
Roast the acorn squash
Drizzle the squash with 1 tablespoon (14g) of the olive oil and season with salt & pepper. Place cut side down on the baking sheet and roast until the flesh is fork tender, about 45 minutes.
Cook the rice
Add the wild rice and 1½ cups (355ml) of water to a medium saucepan. Bring to a boil over medium heat, then cover and lower heat to medium-low and simmer until tender, about 30 minutes.
Heat 3 tablespoons (41g) of the oil in a large sauté pan, add the mushrooms and cook, stirring frequently, until the mushrooms have reduced in size slightly, about 3 minutes. Season with salt and pepper.
Add shallots and garlic
Add the shallots and garlic, continuing to cook until the mushrooms are golden brown and the shallots are soft, about an additional 4 minutes.
Add the kale, stirring to combine. Cook until reduced in size, about 3 minutes. Stir in vegetable broth and cook until the broth has evaporated and kale is tender, about 6 to 8 minutes.
Make walnut mixture
Add walnuts, remaining tablespoon (14g) of oil, soy sauce, honey, chili powder, cumin, and cayenne to the bowl of a food processor fitted with a blade attachment or blender. Pulse until finely diced.
In a large mixing bowl combine the rice, mushroom and kale mixture and walnut mixture, stirring to combine. Divide among the roasted halves of acorn squash and place on a baking sheet.
Heat and serve
Return the stuffed squash to the oven and bake until warmed through, about 15 minutes. Serve immediately.