Cut the steak into small sections, then season it with the Mrs. Dash seasoning.
In a large skillet, pour in the vegetable oil, then turn the heat to medium-high.
Once the oil is nice and hot, add in the steak, onions, and peppers. Cook for about 5 minutes, then add in the mushrooms.
Cook for an additional 3-5 minutes, or until the steak is cooked to your preference, then remove the ingredients from the skillet.
Place three flour tortillas down, then top them with the steak, onions, peppers, and mushrooms.
Add as much or as little of the cheeses on top of the peppers/steak , then place another tortilla on top.
Place the quesadilla on grill or quesadilla maker, and grill until the flour tortilla is golden, and the cheese melts.
Cut the quesadilla, and serve!