Heat oil in a medium soup pot and sauté the onion and garlic for 2 to 3 minutes. Add the mushrooms and sauté another 4 to 5 minutes. Add all remaining ingredients except the avocado. Cover, bring to a boil, reduce the heat to medium-low and simmer about 20 minutes until peppers are tender. Serve with slices of avocado garnish.
Per serving - 323 calories, 12 g fat (30% calories from fat), 14 g protein, 46 g carbohydrate, 13 g fiber, 0 mg cholesterol, 584 mg sodium