In a skillet cook sausage till no pink remains. Drain fat. Stir in pizza sauce and mushrooms; heat through.
Hollow out bottom halves of rolls. Spoon in meat mixture. Top with pepper rings and cheese. Cover with bun tops.
Place sandwiches in a shallow baking pan or on a baking sheet. Cover tightly with foil and heat in a 375° oven for 15 minutes or till cheese melts and sandwiches are hot.
Microwave directions: In a 1-1/2-quart casserole micro-cook sausage, covered, on 100% power (high) for 4 to 6 minutes or till no pink remains, stirring twice. Drain fat. Stir in pizza sauce and mushrooms. Cook, uncovered, on high for 2 to 3 minutes or till heated through. Assemble and bake sandwiches as above.