Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Once shimmering, add sliced onions, bell peppers, and mushrooms. Sauté for 5-7 minutes until softened and caramelized.

Push the vegetables to one side. Add the ribeye steak and cook for 2-3 minutes until browned, then mix with the vegetables and remove from heat.

Drizzle Worcestershire sauce over the mixture and season with salt and pepper, stirring for 1 minute.

Lay tortillas flat and sprinkle cheese over half. Spoon the steak and vegetable mixture on top and add another layer of cheese. Fold the tortilla over.

Return the skillet to medium heat, adding more oil if needed. Cook the folded quesadillas for 2-3 minutes each side until golden brown and crisp.

Once golden, remove from skillet, slice into wedges, and serve hot.