Add all of the ingredients to a medium-sized pot and cook over low heat, stirring often until hot and thick. Keep warm.
Sandwich
Add one tablespoon of clarified butter to a large frying pan over medium-high heat and cook the onions, and peppers until lightly browned and soft, about 10 minutes. Set to the side.
Add the remaining tablespoon of clarified butter to the pan and add in the sliced steak.
Cook for 2-4 minutes or until lightly browned and cooked throughout.
Add half of the cooked onions and peppers to the top of the beef, season with salt and pepper, and mix together until combined.
Assembly
Toast the buns
Evenly divide the sliced cooked steak between the lightly toasted buns and top off with the remaining peppers and onions and cheese sauce.
Notes
To slice the ribeye thinly, freeze for 30 minutes or until stiff but cuttable. Use a heavy SHARP knife.