Toast the sunflower seeds in the oven for about 7 minutes, or until lightly browned; remove from oven, leaving it at 350.
In a skillet, saute the shallots, onion, and leek in olive oil for 5 minutes over medium heat. Add the mushrooms, celery, sunflower seeds, barley, herbs and tamari and continue sauteing for 5 more minutes, stirring frequently.
Add the vegetable stock to the barley mixture. Bring to a boil and transfer the mixture to a casserole dish.
Bake, covered for 1 1/4 hours.
For those gluten free, you could try it with quinoa. You would not have to cook so long as quinoa cooks much quicker, I cooked it with quinoa and baked for about 45 minutes. Also, you would want to decrease the broth to just 2 - 2.5 cups instead of 3 cups.
If you didn't want to toast the sunflower seeds, just buy roasted sunflower seeds and skip the roasting step!