In a nonstick pan, heat 2 tablespoons of melted coconut oil or olive oil over medium-high heat. Add one diced large yellow onion, 2 tablespoons of ginger paste, and 4 cloves of minced garlic. Sauté this mixture for about 3-6 minutes until the onion is golden and fragrant.

Stir in 1 teaspoon each of smoked paprika, ground cumin, and ground turmeric, along with a pinch of salt, 2 teaspoons of garam masala, and optional red pepper flakes. Cook for an additional 1-3 minutes until the spices are aromatic.

Add a 14-ounce can of fire-roasted diced tomatoes, scraping the pan's bottom. Allow the mixture to cool slightly before transferring it to your slow cooker.

Trim excess fat from about 1.5 pounds of boneless skinless chicken thighs and place them in the slow cooker. Pour the aromatic tomato sauce over the chicken.

Cover the slow cooker and set it to cook on ‘high’ for 2.5-4 hours or ‘low’ for 4-6 hours until chicken reaches 165°F.

Once cooked, remove the chicken thighs and chop into bite-sized pieces. Blend the remaining sauce until smooth and return it to the slow cooker.

Stir in 4 tablespoons of unsalted butter and 1 cup of heavy cream. Mix thoroughly until well combined, allowing the butter to melt completely.

Taste the sauce and adjust seasoning as necessary. Serve hot, garnished with finely chopped cilantro, alongside fluffy rice or warm naan.