Preheat your oven to 400 degrees F and grease a 9x13 baking dish.

Slice each green bell pepper from the top down through the core, discarding the core, seeds, and membrane. Place the hollowed peppers in the greased baking dish and bake for about 15 minutes.

Heat half of the olive oil in a large skillet over medium-high heat. Add the shaved steak, stirring and breaking it into small pieces, and cook for 5-7 minutes until fully cooked. Transfer the steak to a plate.

In the same skillet, add the remaining olive oil. Add the thinly sliced onion and red bell pepper and sauté for 5 minutes until softened. Mix in the chopped mushrooms and continue cooking for another 2 minutes.

Return the cooked steak to the skillet with the vegetables. Add the Worcestershire sauce, kosher salt, and black pepper. Break two slices of provolone cheese into the mixture and stir until melted and well combined.

Remove the baked green peppers from the oven and carefully divide the meat and vegetable mixture among them. Top each pepper with a slice of provolone cheese.

Return the stuffed peppers to the oven and bake for an additional 15 to 30 minutes, depending on desired tenderness.