Add ketchup, brown sugar, BBQ sauce, honey, cider vinegar, Worcestershire sauce, onion powder, and black pepper to a small saucepan over high heat. Stir occasionally. The moment you see small bubbles forming around the edges, remove from heat immediately. Do not let it reach a rolling boil or the sugar may scorch.

Let the sauce cool completely to room temperature. It will thicken as it cools. Transfer to a jar and refrigerate if making ahead.

Preheat grill to medium heat. Using a sharp serrated knife, score each hot dog with diagonal cuts about halfway through, spaced evenly to form a W pattern down the length. Do not cut all the way through.

Place hot dogs on the grill and cook 3 to 5 minutes per side until nicely charred. Flip once halfway through. The cuts will cause the dogs to curl slightly as they cook.

Butter the inside of each bun and place cut side down on the grill for about 1 minute until lightly golden at the edges. Do not over-toast.

Place each grilled hot dog in a toasted bun and top generously with the special sauce. Add optional toppings such as white onions, sauerkraut, pickles, or banana peppers. Wrap in foil to keep warm if serving a crowd.