Lightly reheat the leftover pulled pork in a microwave. (It doesn't have to be piping hot. Warm pulled pork is easier to spread.)
Heat a large skillet over medium high heat. Lightly sweep butter all over the bottom of the skillet, as pictured below. (TIP: Use a cold stick of butter.)
Place 2 tortillas side by side, creating half circles with each tortilla.
On one half of each tortilla, sprinkle 1-2 tablespoons of cheese, then about ¼ cup of pulled pork, fresh cilantro, if using, and another 1-2 tablespoons of cheese. Fold other half of the tortilla over the filling.
Cook for about 2 minutes, or until the bottom of the tortilla is golden brown and crispy. Slide a spatula under the quesadilla from the folded side and flip. If needed, you can butter the skillet again when you lift the quesadilla before flipping. Cook for another minute or two, or until nice and golden.
Continue with the remaining quesadillas. Cut the quesadillas into triangles and serve immediately with salsa and sour cream for dipping.
Notes
Note 1: I like to use 8-inch tortillas, but you can use 10-inch tortillas as well. Just make sure to increase the filling accordingly. Also, I recommend flour tortillas over corn tortillas.Note 2: You can use any blend of cheese. I like the combination of Monterey Jack and sharp cheddar. Monterey Jack melts nicely, and sharp cheddar adds great flavor!