Here are the following ingredients:
Here are the following shopping items to buy:
Follow these cooking methods/directions:
Pat beef strips dry with paper towel; season with half each of the salt and pepper.
Heat half the oil over medium-high heat in large nonstick skillet; cook beef strips and garlic for 4 to 5 minutes, stirring, until cooked to medium (160ºF/71ºF) and browned but just slightly pink inside. Transfer to a bowl.
Add remaining oil to skillet; cook mushrooms, onion, rapini, Italian seasoning, hot pepper flakes and remaining salt and pepper, stirring often, for 5 to 7 minutes or until softened. Return beef with any accumulated juices to skillet and toss to combine. Remove from heat.
Meanwhile, spread garlic butter on cut sides of buns. Place buttered-side up on a rimmed baking sheet. Broil for 2 minutes until bread is lightly toasted. Arrange cheese slices inside each bun; broil for 2 minutes until cheese is melted. Using tongs, fill each bun with the beef mixture. Top with pickled peppers.