Combine the prepared barbecue sauce, bourbon, brown sugar, apple cider vinegar, Dijon mustard, and Worcestershire sauce in a saucepan. Bring the mixture to a gentle simmer over medium heat and cook for 8–10 minutes, stirring occasionally, until slightly thickened; set aside.

Gently mix the ground beef with the kosher salt and freshly ground black pepper. Form twelve patties of about 2 1/2 ounces each, making them slightly wider than the buns because the beef will shrink as it grills.

Chill the formed patties for 15–20 minutes so they hold together better on the grill. Meanwhile, prepare the bacon and toppings.

Grill the bacon over indirect heat or cook it in a skillet until browned and crisp, about 10–15 minutes. Drain it on paper towels, watching carefully for flare-ups if cooking on the grill.

Preheat the grill to medium-high, approximately 375–400°F. Grill the beef patties for about 3–4 minutes per side, or until the centers reach 160°F.

During the final 1–2 minutes of cooking, brush the patties generously with bourbon barbecue glaze. Turn them once and brush the second side, then add Cheddar during the final minute and close the grill briefly to melt it.

Toast the cut sides of the slider buns, adding butter or mayonnaise first if desired. Place each glazed patty on a bun and top with bacon, dill pickles, and thinly sliced red onion.

Serve the sliders immediately with any reserved glaze. Never reuse glaze that has touched raw beef unless it has been boiled again first.