Step 1: Dry the Chicken - Start by patting the chicken thighs dry with paper towels. I know this feels like a tiny step, but it matters because dry chicken browns better. If the skin is wet, it steams in the skillet instead of getting that golden color. Take a minute here and you will be rewarded later with chicken that looks and tastes richer before it even goes into the slow cooker.
Step 2: Season Both Sides - Season both sides of the chicken thighs with the salt, black pepper, garlic powder, and smoked paprika. I like to lay the chicken out on a board or plate so I can see every piece and make sure nobody gets missed. The seasoning is simple, but it gives the chicken a savory, smoky foundation that stands up nicely to the sweet cranberry barbecue sauce.
Step 3: Sear the Chicken - Heat the oil in a large skillet over medium high heat. Place the chicken thighs skin side down and let them cook for 4 to 5 minutes, until the skin is deeply golden. Try not to move them around too much. Let the skillet do its job. Flip the chicken and cook for another 2 minutes on the other side. This step adds flavor, helps the skin hold together, and makes the finished dish feel more like Sunday dinner than slow cooker chicken.
Step 4: Move the Chicken to the Slow Cooker - Transfer the seared chicken thighs to a 6 quart slow cooker, placing them skin side up. That skin side up position helps keep the top from getting too soggy while the chicken cooks. Do not worry if the chicken is not cooked through yet. It is supposed to finish slowly in the sauce, soaking up all that sweet, smoky, tangy flavor as it becomes tender.
Step 5: Mix the Cranberry BBQ Sauce - In a medium bowl, whisk together the whole berry cranberry sauce, barbecue sauce, brown sugar, Dijon mustard, apple cider vinegar, Worcestershire sauce, onion powder, and dried thyme. The cranberry sauce may look a little chunky at first, and that is fine. As it warms in the slow cooker, it loosens into the barbecue sauce and becomes a rich glaze with little bits of cranberry throughout.
Step 6: Pour the Sauce Over the Chicken - Pour the sauce around and over the chicken thighs. I like to spoon a little over the top of each piece so every thigh gets coated right from the start. The sauce will seem generous, but that is exactly what you want because it thickens later and becomes the good stuff everyone wants drizzled over potatoes, rice, or noodles.
Step 7: Slow Cook Until Tender - Cover the slow cooker and cook on low for 5 to 6 hours or on high for 3 to 4 hours. The chicken is done when it is tender and reaches an internal temperature of 165 degrees Fahrenheit. Low is my favorite setting here because it gives the chicken time to relax and soak in the sauce. By the time dinner rolls around, the meat should be juicy and tender enough to make everyone quiet for the first few bites.
Step 8: Rest the Chicken - Carefully transfer the chicken to a platter and loosely tent it with foil. Be gentle because the thighs will be tender after slow cooking. This little rest keeps the chicken warm while you thicken the sauce. It also gives you a chance to get your sides finished, call everyone to the table, and pretend the kitchen was under control the whole time.
Step 9: Thicken the Sauce - In a small bowl, whisk together the cornstarch and cold water until smooth. Stir that mixture into the sauce in the slow cooker. Turn the slow cooker to high, leave the lid slightly ajar, and cook for 15 to 20 minutes, stirring occasionally. The sauce will tighten up into a glossy glaze that clings to the spoon instead of running right off.
Step 10: Glaze and Serve - Return the chicken to the slow cooker and spoon the thickened glaze generously over each piece. If you want a little extra caramelized finish, you can place the glazed chicken under the broiler for 2 to 3 minutes before serving. Sprinkle with chopped parsley and a few cranberries if you like that pretty holiday look. Serve it warm with plenty of extra sauce because someone will absolutely ask for more.