Spray your crockpot with nonstick spray. Add the chicken to the crockpot.
2 pounds boneless, skinless chicken thighs
Heat the ghee in a large skillet over medium heat until melted. Add in the onion and cook until softened, about 5-7 minutes.
2 tablespoons ghee, 1 onion
Add in the serrano, garlic, ginger, garam masala, coriander, cumin, turmeric, and salt. Cook until fragrant, about 1-2 minutes.
1 serrano chili, 4 cloves garlic, 1 tablespoon minced ginger, 1 tablespoon garam masala, 1 teaspoon ground coriander, 1 teaspoon ground cumin, ½ teaspoon ground turmeric, ½ teaspoon kosher salt
Add in ¼ cup water and scrape up any browned bits from the bottom of the pan. Transfer to the slow cooker.
To the crockpot, add in the tomato sauce and stir to combine. Cover and cook on low for 3 hours.
15 ounces tomato sauce
Stir in the yogurt and serve topped with cilantro.
⅔ cup whole milk yogurt, ¼ cup chopped fresh cilantro