1 onion, chopped fine 6 garlic cloves minced 1/4 ounce dried porcini mushroom, rinsed and minced 1 teaspoon canola oil 6 cups water 4 cups vegetable broth 1 pound portobello mushroom caps, gills removed, caps halved and sliced thin 3 stalks lemon grass, trimmed to bottom 6 i