Directions

1. Prepare outdoor grill for direct grilling over medium heat. Spray large skillet with cooking spray; heat 1 minute over medium-high heat. Add mushrooms, taco seasoning and black pepper; cook 10 minutes or until very tender, golden brown and all liquid has evaporated, stirring occasionally. Cool slightly.
2. Spray second large skillet with cooking spray; heat 1 minute over medium heat. Add onion and jalapeño peppers; cook 8 minutes or until very tender and golden brown, stirring occasionally.
3. In large bowl, thoroughly mix ground beef and mushroom mixture; form into 4 (½-inch-thick) patties. Make shallow indentation in center of each patty.
4. Spray both sides of patties with cooking spray; place on hot grill rack, cover and cook 8 minutes or until internal temperature reaches 160°, turning once. About 4 minutes before burgers are done, grill bread until grill marks appear, turning once. About 2 minutes before burgers are done, top burgers with cheese.
5. Serve burgers on bread topped with onion-pepper mixture, salsa and avocado.