Lamb Vindaloo

Add the dried red chilies, coriander seeds, cumin seeds, cloves, cardamom pods, cinnamon, black pepper, garlic, ginger, vinegar, tamarind paste, and ¾ cup water to a blender. Blend for 1-2 minutes until a smooth paste forms.
Add the lamb to a large bowl and coat evenly with the ground vindaloo paste. Cover and marinate for 30 minutes at room temperature or up to 8 hours in the refrigerator.
Heat oil in a heavy-bottom pot over medium heat for 2 minutes. Add the chopped onion and cook for 6-8 minutes, stirring often, until softened and lightly golden.
Add curry leaves and ground turmeric. Cook for 30 seconds, stirring constantly to prevent scorching.
Add the marinated lamb along with all the paste. Cook uncovered for 10-12 minutes, stirring every 2-3 minutes, until the masala thickens and coats the lamb.
Add sugar, salt, and 1½ cups of warm water. Stir well, bring to a gentle simmer, then reduce the heat to low. Cover and cook for 60 minutes, stirring every 15 minutes, until the lamb is tender and the sauce has thickened.
Uncover and simmer for an additional 5-10 minutes to adjust consistency. Taste and adjust salt if needed. Turn off the heat and rest for 10 minutes. Garnish with chopped cilantro before serving.