In a large skillet over medium heat, combine pulled pork, BBQ sauce, apple cider vinegar, and brown sugar.
Stir well and cook for 10-12 minutes, stirring occasionally, until pork is heated through and sauce is bubbling. If mixture seems dry, add a splash of water.
While pork is heating, slice buns in half and butter the cut sides. Toast them cut-side down in a separate skillet or griddle until golden brown, about 2-3 minutes.
If using cheese, place one slice on the bottom half of each toasted bun while still warm so it starts to melt.
Pile a generous amount of BBQ pulled pork onto each bun bottom (about 1/2 cup per sandwich).
Top with coleslaw and pickle slices, then add the bun tops. Serve immediately with extra napkinsāthese are deliciously messy!