Heat oil in large wok with cover (you can use a large frying pan if your wok doesn't have a cover, but you may have to transfer everything to a soup pot later after frying).
Saute the onion, garlic and peppers on medium-high heat until onions are translucent, about 10 minutes, stirring frequently.
Stir in barley and soy butter and cook for another 5 minutes.
Reserve 1 cup of diced mushrooms. Add the rest to the wok and stir in well.
Add chicken-flavored broth and cook until liquid is largely evaporated, about 15-20 minutes, stirring frequently.
When liquid is gone, reduce heat to low, add vegetable broth and cover. Simmer until barley is tender, about 20 minutes. There should be a good amount of liquid left.
Using a food processor or blender, blend reserved mushrooms, nutritional yeast and soy milk very well, until creamy.
Add mushroom cream mix to soup and heat through, stirring frequently. Do not boil. Season with salt and pepper to taste.