To mimic those charred, crispy edges like oven- or grill-braised ribs, preheat your broiler to high and line a baking sheet with foil for easy cleanup. Arrange the cooked ribs in a single layer on the sheet and brush generously with some of the thickened sauce.
Broil the ribs 3 to 5 minutes, watching closely, until the sauce is bubbling, shiny, and starting to char at the edges. This step deepens the flavor and gives you that barbecue-shop look. Remove from the oven and let rest a few minutes.
Transfer the ribs to a serving dish or back into the warm, empty slow cooker and spoon more of the remaining sauce over the top. Serve hot, with extra sauce on the side for drizzling over each portion.
For a smokier flavor, choose a hickory or mesquite-style barbecue sauce and add a few drops of liquid smoke to the sauce-and-cola mixture (still keeping the ingredient list to the three main components of ribs, barbecue sauce, and cola). If you prefer a bit of heat, use a spicy barbecue sauce or stir a spoonful of hot sauce into the bottle before mixing with cola. You can also swap the cola for root beer or Dr Pepper for a different but still nostalgic sweetness that caramelizes beautifully. To keep things on the sweeter, more kid-friendly side, choose a mild, thick sauce with a touch of brown sugar. For extra char, broil the ribs a second time with another thin layer of sauce, just a minute or two, to build up a lacquered crust. If you’re cooking for two, halve the recipe but keep the same cooking time; the ribs still need that low, slow braise to become fall-apart tender. Leftovers reheat well covered in the oven with a splash of water or extra sauce, or you can shred the meat and mix it with some of the cooking juices for pulled pork sandwiches or taco fillings.