Unsloppy Joes

I got this one from Chelsea as well

1 tablespoon olive oil
1/2 cup chopped onion
1/2 cup chopped celery
1/2 cup chopped carrots
1/2 cup chopped green bell pepper
1 clove garlic, minced
1 (14.5 ounce) can diced tomatoes
1 1/2 tablespoons chili powder
1 tablespoon tomato paste
1 tablespoon distilled white vinegar
1 teaspoon ground black pepper
1 (15 ounce) can kidney beans, drained and rinsed
8 kaiser rolls or whole wheat hamburger buns

Heat olive oil in a large skillet over medium heat. Add onion, celery, carrot, green pepper, and garlic: saute until tender. Stir in tomatoes, chili powder, tomato paste, vinegar, and pepper. Cover, reduce heat, and simmer 10 minutes.
Stir in kidney beans, and cook an additional 5 minutes.
Cut a 1/4 inch slice off the top of each kaiser roll; set aside. Hollow out the center of each roll, leaving about 1/2 inch thick shells; reserve the inside of rolls for other uses.
Spoon bean mixture evenly into rolls and replace tops. Serve immediately.