Heat olive oil in a large saucepan over medium heat. Stir in onions, and cook until soft and translucent. Add garlic, and cook one minute, stirring frequently so garlic doesn't burn.
Add vegetable broth, beans, chili powder, cumin, and salt. Bring to a boil. Reduce heat, and simmer uncovered for 30 minutes.
Yield: 8 servings (serving size: 1 cup)