Step 1 - Season the Chicken for Full Flavor: Pat the chicken thighs dry with paper towels and season them all over with salt, black pepper, smoked paprika, and garlic powder. Take a second to really rub the seasoning into the skin and meat. This little bit of attention makes a big difference in flavor later.
Step 2 - Sear the Chicken for Color and Depth: Heat the oil in a large skillet over medium high heat. Once hot, place the chicken thighs skin side down in the pan. Let them sear until the skin is deeply golden and a little crisp at the edges. This step builds flavor and keeps the skin from tasting greasy later.
Step 3 - Transfer to the Slow Cooker for Gentle Cooking: Move the seared chicken thighs into your slow cooker, placing them skin side up. Try to keep them in a single layer so they cook evenly and stay tender.
Step 4 - Whisk the Sauce for Balanced Flavor: In a medium bowl, whisk together the barbecue sauce, Dr Pepper, brown sugar, Worcestershire sauce, apple cider vinegar, and Dijon mustard until smooth and glossy. This sauce is the heart of the recipe so give it a good stir.
Step 5 - Pour Sauce Around the Chicken to Protect the Skin: Carefully pour the sauce around the chicken in the slow cooker, not directly over the skin. This helps the skin keep some texture while still letting the chicken soak up all that flavor as it cooks.
Step 6 - Slow Cook Until Tender and Juicy: Cover and cook on low for 5 to 6 hours, until the chicken is tender and cooked through. You will know it is ready when the meat pulls easily from the bone.
Step 7 - Thicken the Sauce for a Glossy Finish: Remove the lid during the last 30 to 45 minutes of cooking to allow the sauce to reduce and become thick and glossy. This step turns the sauce into something you will want to spoon over everything on your plate.
Step 8 - Broil for Extra Texture if You Like Crisp Skin: If you want a little extra texture on the skin, place the chicken thighs under the broiler for a few minutes just to caramelize the skin slightly. Stay close to the oven because this step happens fast.
Step 9 - Spoon Sauce Over the Chicken for Maximum Flavor: Right before serving, spoon the thickened sauce over each piece of chicken. This makes sure every bite gets coated in that sweet smoky goodness.