In a pan on medium heat, add olive oil.

Slice onion, and chop slices in half, adding to pan once heated.

Once the onions begin to soften (after about 5 minutes), add sliced green pepper, and minced garlic, cooking for about two minutes.

Add in sliced steak, along with salt & pepper to taste.

Cook until steak is done to your liking (should only take a few minutes). Add more salt & pepper if necessary.

Spread butter on the outside of each slice of bread, spread mayonnaise on the inside of both slices.

Place steak mix on bread, top with provolone cheese and bread.

Place in pan, turn heat to medium, cooking until golden brown on each side.