Steps
1. Heat the olive oil in a skillet over medium heat.
2. Add the bell pepper, mushrooms and onion, season with salt and pepper and cook until the vegetables are lightly browned, about 8 minutes.
3. Meanwhile, warm up the tortilla in the microwave for about 10-15 seconds.
4. Remove the vegetables from the heat and place them on a plate.
5. Place the tortilla on the skillet over medium heat and spread the vegetables and corn over the it.
6. Sprinkle the cheese over the vegetables and season with salt and pepper.
7. Fold the tortilla over the fillings, cook for about 2 minutes, until the cheese is melted and the tortilla is golden.
8. Transfer the quesadilla to a cutting board, cut it in half, and serve with tomato salsa.