01 - Combine beef cubes 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 refrigerate for 30 minutes minimum, or overnight for enhanced flavor penetration.
02 - Layer the sliced onions, chopped tomatoes, cubed potatoes, and slit green chilies at the bottom of the slow cooker insert, creating an even vegetable bed.
03 - Arrange the marinated beef over the vegetable layer, scraping any remaining marinade from the bowl onto the meat.
04 - Sprinkle curry powder or garam masala, ground cumin, smoked paprika, bay leaves, cinnamon stick, whole cloves, and cardamom pods evenly over the beef.
05 - Pour beef broth and coconut milk into the slow cooker. Stir gently to distribute spices without disturbing the vegetable layer. Cover and cook on LOW for 8 hours or HIGH for 4 hours until beef is fork-tender and sauce has thickened.
06 - Remove and discard bay leaves, cinnamon stick, cloves, and cardamom pods. Taste the curry and adjust seasoning with additional salt and pepper if desired. Garnish generously with fresh chopped cilantro and serve hot alongside steamed basmati rice or warm naan bread.