In a bowl, toss the steak with olive oil, chili powder, cumin, garlic powder, salt, and pepper.
Heat a large skillet over medium-high heat. Add the steak and cook for 3-5 minutes, or until browned and cooked through. Remove steak from skillet and set aside.
In the same skillet, add the chopped bell pepper and onion. Cook until softened, about 5 minutes.
Lay out the tortillas. Sprinkle half of each tortilla with shredded cheese, then top with cooked steak, and bell pepper and onion mixture. Sprinkle with more cheese.
Fold the other half of the tortilla over the filling. Cook the quesadillas in the skillet over medium heat for 2-3 minutes per side, or until golden brown and the cheese is melted.
Cut into wedges and serve immediately with your favorite toppings like salsa, sour cream, or guacamole.
Notes
Feel free to add other vegetables like corn or mushrooms. Adjust spices to your preference.