Begin by finely dicing the yellow onion, mincing the garlic, and grating the ginger.

In a skillet, heat 1 tbsp of unsalted butter over medium heat. Add the diced onions and sauté for 5-7 minutes until translucent.

Stir in the minced garlic and grated ginger into the skillet. Cook for an additional minute.

Add the garam masala, ground cumin, turmeric, paprika, and cayenne pepper to the skillet. Sauté briefly for another 30 seconds.

Transfer the sautéed onion mixture to the slow cooker. Pour in the tomato sauce, brown sugar, salt, and black pepper, stirring well to combine.

Place the chicken thighs into the sauce, ensuring they are mostly submerged.

Set slow cooker to LOW for 4 hours or HIGH for 2 hours.

Once complete, use two forks to shred the chicken right in the slow cooker.

In a separate bowl, whisk together the heavy cream and yogurt until smooth. Stir this into the slow cooker along with the remaining butter.

Gently mix everything and set the slow cooker on LOW for an additional 15-20 minutes.

Before serving, taste the dish and adjust seasoning as needed. Garnish with chopped cilantro.