Heat 1 tablespoon of olive oil in a pan over medium-high heat. Add the sliced steak and cook until browned and cooked to your desired doneness. Remove and set aside.
In the same pan, add the remaining olive oil and sauté the bell pepper and onion until softened.
Lay out the tortillas and sprinkle half of each with shredded cheese, followed by steak, vegetables, and more cheese. Fold the tortillas in half.
Cook the quesadillas in a large pan or griddle over medium heat until the tortillas are golden and the cheese is melted, about 3-4 minutes per side.
Notes
Serve with sour cream, salsa, or guacamole if desired.