Pulled BBQ Chicken Sandwiches

* 1 tablespoon canola oil
* 1 large onion, chopped
* 3 cloves garlic, minced
* 1 (14-ounce) can low-sodium tomato sauce
* 1/4 cup tomato paste
* 1/2 cup water
* 1/3 cup apple cider vinegar
* 5 tablespoons molasses
* 1/4 teaspoon ground black pepper
* 1/2 teaspoon liquid smoke
* 1 whole rotisserie chicken, skin removed, meat shredded into thin strips (about 4 to 4 1/2 cups)
* 6 whole-wheat hamburger rolls
* 6 large green lettuce leaves

Directions

Heat the oil in a large saute pan over a medium heat. Add the onions and cook until they are soft and translucent, about 5 minutes. Add the garlic and cook for 1 minute more. Add tomato sauce, tomato paste, water, vinegar, molasses, pepper and liquid smoke and bring to a boil. Reduce heat to medium-low and simmer for 15 minutes. Add chopped chicken, return to a simmer, and cook an additional 10 minutes.

Split rolls. Place a leaf of lettuce on each roll, then pile on 3/4 cup of the chicken mixture onto the roll.