In a large skillet, heat the olive oil over medium heat. Add the chopped onion and bell pepper. Sauté for about 3-4 minutes until they begin to soften. Stir in the minced garlic and cook for an additional minute until fragrant.
In a mixing bowl, combine the drained black beans, corn, salsa, light brown sugar, cumin, and chili powder. Mix well to ensure all the ingredients are evenly coated.
Lay a tortilla flat on a clean surface. Sprinkle a generous amount of shredded cheese on half of the tortilla, followed by a portion of the vegetable and bean mixture. Top with another layer of shredded cheese before folding the tortilla over to create a half-moon shape.
In the same skillet, place the folded quesadilla and cook for about 3-4 minutes on one side until golden brown and crispy. Carefully flip it over using a spatula, and cook for an additional 3-4 minutes on the other side. Repeat this process with the remaining tortillas and filling.
Once cooked, remove the quesadillas from the skillet and let them cool for a minute. Cut each quesadilla into wedges and serve warm with a dollop of sour cream on the side.
