Preheat the oven to 400 degrees. Toss the mushrooms with salt and pepper. Use a cooking spray to spray a baking sheet and place the mushrooms on the sheet, trying not to overcrowd and overlap.
Place the baking sheet in the oven and roast the mushrooms for 20-25 minutes until they are dried out. Place the mushrooms in a food processor and pulse 10-15 times or until you have a coarse mince. Set aside.
Heat the oil. Add the onions, carrots, and celery. Season with salt and pepper and saute until the vegetables are softened and the onions translucent, about five minutes on medium heat
Add the garlic and thyme. Stir well to mix for about a minute. Add green peas and saute until thawed and warmed through, about three to four minutes.
Add the quinoa, minced mushrooms and tamari. Mix well and let it all heat through. Add more salt and ground black pepper if needed. Turn off the heat and set aside.