Step 1: Prepare the Vindaloo Paste: In a small pan, lightly toast the dried chilies, coriander seeds, cumin seeds, and black peppercorns over medium heat until fragrant (about 1-2 minutes). Be careful not to burn them. Let cool slightly.
Step 2: Transfer the toasted spices to a blender or small food processor. Add the ginger, garlic, red wine vinegar, ground cloves, and ground cinnamon. Blend until a smooth paste forms. Add a tablespoon or two of water if needed to help it blend, but keep it as thick as possible.
Step 3: Marinate the Chicken: In a large bowl, combine the chicken pieces with the prepared vindaloo paste. Mix well to ensure all chicken is coated. Cover the bowl and refrigerate for at least 2 hours, preferably 4 hours or overnight, to allow the flavors to meld for this slow cooker chicken vindaloo recipe.
Step 4: Sear the Aromatics and Chicken: Heat the vegetable oil in a large skillet or Dutch oven over medium-high heat. Add the chopped onion and sauté until softened and lightly golden, about 5-7 minutes.
Step 5: Add the marinated chicken to the skillet, reserving any excess marinade in the bowl. Sear the chicken for 3-4 minutes, browning it lightly on all sides. You don't need to cook it through at this stage.
Step 6: Assemble in Slow Cooker: Transfer the seared chicken and onions to your slow cooker. Pour in any reserved marinade from the bowl. Add the diced tomatoes (undrained) and 1/2 cup of water or chicken broth. Stir gently to combine.
Step 7: Cook: Cover and cook on LOW for 6-8 hours or on HIGH for 3-4 hours, until the chicken is incredibly tender and easily pulls apart with a fork. The longer, slower cook time is ideal for developing deep flavors in your slow cooker chicken vindaloo recipe.
Step 8: Finish and Serve: Once cooked, stir in the sugar and salt to taste. The sugar helps balance the acidity and heat. If the sauce is too thin, you can remove the lid and cook on high for an additional 30 minutes, or thicken with a cornstarch slurry if desired. Garnish generously with fresh cilantro before serving. This slow cooker chicken vindaloo recipe is best served hot with basmati rice or naan.