Pour the remaining BBQ sauce mixture evenly over the ribs, turning them with tongs to make sure every piece is well coated. Spoon some sauce from the bottom over any spots that look dry.
Cover the slow cooker with the lid and cook on LOW for 7–8 hours, or on HIGH for 3 1/2–4 hours, until the ribs are very tender and easily pull apart with a fork.
Once the ribs are cooked and tender, preheat your oven broiler to high and line two rimmed baking sheets or foil trays with aluminum foil for easy cleanup.
Using tongs, carefully transfer the ribs from the slow cooker to the prepared foil-lined trays, letting any excess liquid drip off slightly but keeping plenty of sauce clinging to the meat.
Spoon or brush some of the thickened BBQ sauce from the slow cooker over the top of the ribs in the trays so they are generously coated and glossy.
Place the trays under the broiler on the upper-middle rack for 3–5 minutes, watching closely, until the edges of the ribs are slightly charred and the sauce is bubbly and sticky. Rotate the trays if needed so they brown evenly without burning.
Remove the trays from the oven and let the ribs rest for a few minutes. Spoon any pooled sauce from the bottom of the trays back over the ribs for that extra sticky, saucy finish.
Serve the ribs hot right in the foil trays for a casual, family-style meal, with extra barbecue sauce on the side if anyone likes theirs extra saucy.
