1. Preheat broiler.
2. Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add onion, fennel, and garlic; sauté for 4 minutes. Add sausage, and sauté for 3 minutes or until sausage is lightly browned and vegetables begin to brown.
3. Arrange rolls, cut sides up, in a single layer on a baking sheet; broil 2 minutes or until toasted. Spoon about 2/3 cup sausage mixture on the bottom half of each roll, and top each with 2 tablespoons sauce. Place 2 cheese slices over sauce. Arrange sandwiches on baking sheet; broil 2 minutes or until cheese melts.
This updated version of Sausage Fennel Subs is based on a recipe that originally ran in Cooking Light, May 2010. The recipe was retested and updated for Cooking Light Crave!, Oxmoor House, 2013.