Prepare the Steak:

1. If the steak slices are too large, you can give them a rough chop. Season the steak slices with salt and pepper to taste.

Sauté the Vegetables:

1. In a large skillet, heat 15ml of oil over medium-high heat.
2. Add the sliced onions until its slightly caramelised, about 5-7 minutes.
3. Remove the vegetables from the skillet and set aside.
4. See note 2-3 if you want to add mushrooms or bell peppers.

Cook the Steak:

1. In the same skillet, add the remaining 15ml of oil.
2. Add the seasoned steak slices and cook until they are browned and cooked through, about 2-3 minutes per side.
3. If you’re using a large quantity of meat, you may need to cook it in batches to avoid overcrowding the pan, which can lead to steaming instead of searing.

Assemble the Cheesesteak:

1. Push the cooked steak slices to one side of the skillet and place the sautéed onions on top of the steak slices.
2. Lay the slices of provolone cheese over the steak and onions. Allow the cheese to melt slightly.

Shape and Serve:

1. Using a spatula, carefully scoop up the melted cheese, steak and onion on to the split hoagie rolls.

Add Toppings and serve:

1. You can enjoy the Philly Cheesesteak as is, or you can add optional toppings like sautéed mushrooms, jalapeños, ketchup, mayo, or hot sauce.
2. Serve the Philly Cheesesteaks warm and enjoy!

Remember that the exact ratios and ingredients can vary based on personal preferences and regional variations. Some folks even like to drizzle a bit of olive oil or melted butter on the rolls before assembling. Enjoy your homemade Philly Cheesesteak sandwiches!