01 -
Place steak in the freezer for 30 minutes to firm for ultra-thin slicing. Trim excess fat, then slice into thin strips and season with kosher salt and black pepper.
02 -
Chop the onion and thinly slice the green and red bell peppers. Set aside with sliced mushrooms.
03 -
With a serrated knife, carefully slice hoagie rolls lengthwise about three-quarters through to hinge them.
04 -
Combine softened butter with minced garlic. Spread generously on cut sides of hoagie rolls. Toast rolls, cut side down, on a skillet or griddle over medium heat until golden. Remove and set aside.
05 -
Heat 1 tablespoon vegetable oil in a large skillet or griddle over medium heat. Add chopped onions and cook for 8 to 10 minutes, stirring, until lightly caramelized. Remove onions and reserve.
06 -
Increase skillet heat to medium-high. Add remaining tablespoon of vegetable oil. Once hot, distribute thinly sliced steak in a single layer. Cook steak for 2 to 3 minutes without stirring for a seared crust, then turn. Add bell peppers and mushrooms, cook 2 more minutes, then return onions and toss together.
07 -
Divide steak and vegetable mixture into four equal sections in the pan. Top each with two slices of provolone cheese. Turn off the heat and allow cheese to melt.
08 -
Spread a thin layer of mayonnaise on the cut side of each toasted hoagie roll. Place each roll over a portion of steak, vegetables, and melted cheese, then use a spatula to lift and invert the filling into the roll. Serve immediately while hot.