Preheat oven to 425. Mist cut side of squash with cooking spray, and season with salt and pepper to taste. Lay cut-side-down on baking sheet. Roast for 15 minutes, then flip and roast for another 10 minutes.
While squash is roasting, add quinoa, stock, and seasonings to a small sauce pan. Bring to a boil, cover, lower heat to a simmer, and cook for 15 minutes or until water is fully absorbed. Take off heat and let stand for 5 minutes.
While quinoa is cooking, toast almonds in a skillet over medium heat, watching closely so they don't burn. Set almonds aside.
Raise skillet heat to medium high and add mushrooms. Saute until browned, 5-10 minutes. Season with salt and pepper, then add in remaining ingredients, including cooked quinoa. Mix well.
Divide mixture between the 4 squash halves, return to oven, and bake for 5-10 minutes, until quinoa mixture is slightly toasted.