1 tablespoon olive oil
1 cup onion, minced
1 cup green bell pepper, chopped, about ¼-inch pieces
3 garlic cloves, minced
1 1/2 teaspoon ground cumin
1 1/2 teaspoon chili powder
1 chipotle pepper en adobo sauce, minced
1 pound ground beef
1 8 oz can tomato sauce
1/2 cup ketchup
2 tablespoon packed dark brown sugar
1 tablespoon Worcestershire sauce
6 soft sandwich or hamburger rolls