Put the steak on the grill and cook until the steak reaches desired doneness (I usually like mine about med-rare). Remove from grill and allow the steak to cool a little. Slice steak into thin strips.
Add a tiny bit of oil to a large pan. Sauté peppers, onion, garlic, and mushrooms until tender. Sprinkle top of the vegetables with cilantro and rosemary.
Place 1 tortilla onto the bottom of the pan. Lay out a layer of cheese (about a ¼ cup), then about half of the sliced steak. Then with a slotted spoon add a layer of the pepper mixture.
Top with tomatoes and another layer of cheese. Add another tortilla on top.
When the bottom tortilla is lightly browned and cheese has started to melt, flip and cook on the opposite side. Cut into wedges and serve.