Start by gathering all your ingredients. Slice the onion and set it aside. If you’re adding bell peppers or mushrooms, get them ready to go as well. Ensure your rib-eye is thinly sliced; this will help it cook fast and remain tender.

In a large skillet, heat the soybean oil over medium heat. You want the pan hot enough to sizzle but not so hot that it smokes. This step is crucial; the right heat will prevent your meat from overcooking.

Add the sliced onions (and bell peppers, if using) to the skillet. Sauté them for about 5 minutes or until they become translucent and start to caramelize. This brings out their sweetness, enhancing the overall flavor profile.

Once the onions are ready, move them to the side of the skillet. Increase the heat to medium-high, add the thinly sliced rib-eye to the pan, and season it with the Worcestershire sauce, Dijon mustard, and a dash of salt and pepper. Cook for about 3-5 minutes or until the steak is browned and cooked through.

When the meat is ready, reduce the heat to low. Layer cheese slices over the meat, covering it well. Cover with a lid to allow the cheese to melt and get gooey.

While the cheese melts, slice your Italian rolls. Toast them lightly in a separate skillet or toaster oven until they are warm and slightly crispy.

Finally, take those warm rolls and load them with the cheesy meat mixture. Use a spatula to scoop everything onto the roll. You can add ketchup at this stage if you like—after all, to each their own.