Peel and cube root vegetables. Roast at 220C in 1 tablespoon olive oil for 30 minutes or until tender but not soft. Time will depend on size of cubes.
Finely chop onion, garlic and celery, and in stovetop pan, cook in other tablespoon olive oil until soft. Add quinoa and lightly cook to coat with oil, add stock and bring to the boil.
Add quinoa etc to root vegetables in oven dish, cover and bake at 220C for 1/2 hour or until quinoa cooked and liquid used. Add more stock or water as necessary.
Nice served with side salad and freshly baked bread. Root vegetables make it quite sweet so a sharp dressing on the salad is a nice contrast.