3 tablespoons plain Greek yogurt, plus more for topping
1 tablespoon unsalted butter, melted
Chopped cilantro, optional
Grated lemon zest, optional
Hot cooked rice
Combine first 12 ingredients in a 3- or 4-quart slow cooker. Add chicken thighs and stir gently to coat. Cook, covered, on low 3-4 hours or until chicken is tender.
Preheat broiler. Using a slotted spoon, transfer chicken to a broiler-safe baking pan lined with foil. Broil 4-6 inches from heat for 3-4 minutes on each side or until lightly charred.
Meanwhile, transfer cooking juices from slow cooker to saucepan. Cook, uncovered, over medium-high heat until slightly thickened, 6-8 minutes. Remove from heat and gently stir in yogurt and butter. Serve chicken with sauce. If desired, garnish with chopped cilantro, lemon zest and additional yogurt. Serve with hot cooked rice.