Preheat oven to 400 degrees.
Place your sliced potatoes in a large bowl.
Pour the olive oil over the potatoes, add the seasonings and stir to coat all the slices well.
Place in a single layer on your baking sheet sprayed with nonstick spray.
Bake the potatoes for 20 minutes.
Next, let’s start on the mushrooms.
Place them in your nonstick skillet with the 1/2 stick butter over medium heat.
When the butter is melted and the mushrooms are thoroughly coated, sprinkle the mushroom spice over them.
Saute’ over low heat for 7-8 minutes; set aside.
Next, the onions. Heat oil in a pot or a fryer until it reaches 300 degrees.
Place the onions in a large bowl and pour the buttermilk over them.
Place the fry mix in a large bowl and take a few onions at a time and coat in the mix.
Carefully place onions in the oil a few batches at a time and fry until golden brown; drain on paper towels.
The steaks: season each side with salt, pepper and garlic salt.
Heat your iron skillet until it’s smoking hot!
Sear each side of the steaks well; place a pat of butter on each and place in 400 degree oven for 5-7 minutes for medium rare.
Remove from pan and let rest on cutting board for 10 minutes; slice into thin strips.
Assembly: Spray a large cast iron skillet with nonstick spray.
Layer potatoes on first, 1/2 the cheese, steak, mushrooms,remaining cheese then the onion straws.
Place in a 400 degree oven for 10 minutes until cheese is all melted.
Top with green onions and enjoy!