Add oil to a skillet over medium heat
Once oil is hot enough to sizzle slightly when a drop of water hits it, add the onions, and stir fry until softened
Add peppers, and continue stir frying until peppers are beginning to soften as well
Remove peppers and onions, and add beef (Note: if the skillet is dry after removing onions and peppers, add another tablespoon of oil)
Stir fry beef until mostly browned, then add mushrooms, and continue cooking until beef is done, and mushroom is softened
Stir in peppers and onions, worcestershire sauce, garlic, salt, and pepper, until cream cheese is fairly well incorporated. This should just take a bit of stirring as the cream cheese will begin to melt.
Cover with sliced provolone, and broil over low heat until cheese is melted and beginning to bubble
Remove from oven and serve hot