Vegetarian Chili

1 tablespoon olive oil 
1 medium chopped onion
1 cup chopped carrots 
3 cloves garlic, minced 
1 chopped green bell pepper 
1 chopped red bell pepper 
1 cup chopped celery 
1 tablespoon chili powder 
2 cups chopped fresh mushrooms  (optional)
1 (28 ounce) can whole peeled tomatoes with liquid, chopped 
1 (19 ounce) can kidney beans 
1 tablespoon ground cumin 
1 1/2 teaspoons dried oregano 
1 1/2 teaspoons dried basil 
½ can tomato paste
1 cup vegetable broth (Epicure)

Heat oil in a large saucepan over medium heat. Saute onions, carrots, and garlic until tender. Stir in green pepper, red pepper, celery, and chili powder. Cook until vegetables are tender, about 6 minutes.  Stir in mushrooms, and cook 4 minutes. Stir in tomatoes, and kidney beans.  Season with cumin, oregano, and basil. Bring to a boil, and reduce heat to medium. Cover, and simmer for 20 minutes, stirring occasionally.