01 - In a mixing bowl, combine the shredded chicken with BBQ sauce, tossing until the chicken is evenly coated.
02 - Heat a large skillet over medium heat and lightly grease with butter or oil.
03 - Place a tortilla in the heated skillet. On one half of the tortilla, layer the BBQ chicken mixture, a generous sprinkle of cheese, red onion, and cilantro.
04 - Fold the empty half of the tortilla over to cover the filling, creating a half-moon shape.
05 - Cook for 2-3 minutes until the bottom side is golden brown, then carefully flip and cook the other side for another 2-3 minutes until crispy and the cheese is completely melted.
06 - Remove from skillet and repeat the process with the remaining tortillas and filling.
07 - Slice each quesadilla into wedges and serve immediately while hot.