For the stuffing: In a large pan, heat the olive oil over medium-high heat. Sauté the carrots, celery, onion, and garlic until softened and begining to brown. Add the wild rice and stock to the pan, give it a stir, then cover and bring to a simmer. Cook for 10 minutes. Now add the white rice to the pan, cover, and continue to cook another 8 to 10 minutes until the rice has cooked and fully absorbed the stock.