To make the quesadillas: For each quesadilla, place a buttered tortilla face-down in a skillet over medium heat. Then add ½ cup of cheddar cheese, 6 ham slices, apple slices, and 3 gouda slices, then top with another tortilla. Cook (on both buttered sides) until the tortilla is golden brown and the cheese is melted, approximately 3 or 4 minutes per side. Slice into triangles.

To make the sauce: In a small bowl, combine the sauce ingredients (BBQ sauce and yogurt). Serve alongside the quesadillas for dipping.