Rub roast with brown mustard. Massage in Cajun seasoning and brown sugar.
Heat a large heavy bottom pan over medium high heat.
Place bacon grease in pot and sear roast, rotating sides until browned all over.
Add Coca-Cola, onion, BBQ sauce and water if needed. Liquid should come to half way up the roast.
Reduce heat to low, cover and simmer for about 4 hours or until when pierced with fork, meat pulls away in strands.
Pull pork into strands, toss with a little BBQ sauce diluted in a splash of water.
Toast buttered slider buns with a slice of cheese on the top half.
Pile on the pulled pork and apple carrot slaw.