Heat a large nonstick pan over medium-high heat. Add the oil, and once it’s hot, sauté the onion, garlic, and ginger, stirring occasionally for about 3 to 6 minutes until they turn golden. This step is crucial because it builds the foundational flavors that will infuse your dish. You want the onion to be soft and fragrant.
Add the smoked paprika, ground cumin, ground turmeric, salt, and garam masala to the pan. Stir constantly for 1 to 3 minutes until the spices become fragrant and vivid in color. You’ll notice the beautiful aroma wafting through the air, which is a sign that the spices are toasting perfectly.
Stir in the can of diced tomatoes, scraping the bottom of the pan to release any browned bits. This will elevate the flavor profile as those bits are packed with taste. Let this mixture cool slightly for a couple of minutes, allowing the flavors to meld.
Transfer the tomato and spice mixture into the slow cooker. This is where all the magic happens! Ensure that it’s evenly spread across the bottom of the pot.
Next, trim any large pieces of fat from the chicken thighs, but leave some fat for added flavor. Add the chicken directly to the slow cooker, ensuring it’s coated well in the sauce. You want the chicken to be nestled comfortably, allowing the sauce to envelop it.
Arrange the chicken thighs in a single layer, smooth side down. Cover and cook on high for 2-1/2 to 4 hours or low for 4 to 6 hours until the chicken reaches 165°F. Be sure to check the internal temperature to ensure food safety.
Once the chicken is cooked, remove it from the slow cooker and chop it into bite-sized pieces. This will help it absorb even more of that luscious sauce.
Using an immersion blender, or transferring the sauce to a regular blender, purée the sauce until smooth. This step can take a little time, but it’s worth it for that silky texture that will coat the chicken beautifully.
Return the blended sauce back to the slow cooker. Stir in the butter and heavy cream until fully combined and smooth. You’ll notice that the sauce transforms into a rich and creamy delight that looks irresistible.
Add the chopped chicken back into the sauce. Stir in cilantro if you're using it, and adjust the seasoning as needed. Taste as you go—this is where you can make it just right for your palate!
Serve hot with warm naan and cooked rice on the side. Enjoy the heartwarming flavors of your homemade Crockpot Butter Chicken!