01 - Combine beef with yogurt, lemon juice, ginger-garlic paste, salt, turmeric, coriander, and chili powder in a large bowl. Toss thoroughly to coat all pieces. Cover and marinate for 30 minutes minimum, up to overnight refrigerated for optimal flavor development.
02 - Arrange sliced onions, chopped tomatoes, cubed potatoes, and slit green chilies evenly across the bottom of the slow cooker insert.
03 - Place the marinated beef on top of the vegetable layer, ensuring even distribution.
04 - Sprinkle curry powder (or garam masala), ground cumin, smoked paprika, bay leaves, cinnamon stick, whole cloves, and cardamom pods over the beef.
05 - Add beef broth and coconut milk to the slow cooker. Stir gently to incorporate spices without disturbing the layered ingredients too much.
06 - Cover and cook on LOW setting for 8 hours or HIGH for 4 hours until beef is fork-tender and sauce has thickened appropriately.
07 - Discard bay leaves, cinnamon stick, cloves, and cardamom pods before serving.
08 - Taste and adjust seasoning with additional salt and pepper as desired. Garnish generously with fresh chopped cilantro. Serve hot accompanied by steamed basmati rice or warm naan bread.