Ingredients

3 cups full-fat Greek yogurt
4 tablespoons lemon juice
3 tablespoons ground turmeric
4 tablespoons garam masala
4 tablespoons ground cumin
6 pounds chicken thighs, on the bone
1/2 pound unsalted butter
3 tablespoons neutral oil
4 medium-size yellow onions
8 cloves garlic, peeled and minced
6 tablespoons fresh ginger, peeled and grated or finely diced
2 tablespoon cumin seeds
2 cinnamon stick
28 oz can diced tomatoes
2 red chiles, like Anaheim, or 1 jalapeño pepper, seeded and diced
Kosher salt to taste
1 1/3 cup chicken stock
3 cups half-and-half
1 tablespoon tomato paste
6 tablespoons chopped cashews
1 bunch cilantro leaves, stems removed.

Directions

1. Whisk together the yogurt, lemon juice, turmeric, garam masala and cumin in a large bowl. Put the chicken in, and coat with the marinade. Cover, and refrigerate (for up to a day).
2. In a large pan over medium heat, melt the butter in the oil until it starts to foam. Add the onions, and cook, stirring frequently, until translucent. Add the garlic, ginger and cumin seeds, and cook until the onions start to brown.
3. Add the cinnamon stick, tomatoes, chiles and salt, and cook until the chiles are soft, about 10 minutes.
4. Add the chicken and marinade to the pan, and cook for 5 minutes, then add the chicken stock. Bring the mixture to a boil, then lower the heat and simmer, uncovered, for approximately 30 minutes.
5. Optional: At this point, you can remove the chicken and blend the sauce till it's smooth and creamy, adding the cashews or almonds. Return the sauce to the pan.
6. Stir in the cream and tomato paste; add the chicken back if you did step 5; and simmer until the chicken is cooked through, approximately 10 to 15 minutes.
7. Add the nuts if you haven't already, cook for an additional 5 minutes and remove from the heat. Garnish with the cilantro leaves.