Preheat oven to 450
in a large skillet over medium heat, add olive oil and thinly sliced onion and pepper and saute until soft and darer in color
In a cast iron pan on medium-high heat, add butter, thinly sliced steak, and montreal steak seasoning, and brown. It will cook quickly
Slice baguette long ways, so it is open face. Drizzle with olive oil, place on a baking sheet, and put into oven until lightly toasted
Remove baguette from oven, and rub with garlic while still hot.
Spread mayonnaise, then layer with cooked beef, onions and peppers, and cheese, and put in oven until cheese is melted
Cut to desired sandwich size and enjoy!