In a small bowl, whisk together Worcestershire sauce, garlic powder, salt, black pepper, and olive oil.

Pour the prepared marinade over the shaved steak, ensuring it's well coated. Cover with plastic wrap and let it marinate in the refrigerator. Aim for at least 30 minutes, or longer if time allows.

Set your Blackstone to medium-high heat. Either spray with a high-heat cooking spray or season with vegetable oil to prevent sticking. Cook the sliced onions on the griddle until they're nicely caramelized. Once done, transfer them to a small bowl.

Place the marinated steak on the griddle. Be sure to flip, rotate, and chop vigorously to ensure all pieces are well-cooked and evenly browned. This should take about 5 minutes. The goal is to strike the balance between succulent, tender pieces and some with a nice char.

Once the steak is cooked, remove it from the griddle. Place your hoagie buns, face down, and toast for about a minute each until lightly browned and slightly crispy.

Start with a layer of the cooked steak on the bun, followed by a layer of caramelized onions and a generous spread of Cheez Whiz. Repeat with another layer of steak, onions, and cheese to complete your easy cheesesteak sandwich.