Place the dry red chilies in a blender jar and pour hot water over them. Let them soak in the jar for 10-15 minutes or until they soften.

Once the chilies are soft, you can deseed a few if desired. Drain the soaking water and reserve. To the chilies, add the coriander and cumin seeds along with star anise, black peppercorns, cinnamon stick and cloves. Also add the roughly chopped ginger and garlic.

Add a bit of the soaking water to the blender jar. Blend the chilies and spices into a smooth paste.

Place the lamb pieces in a large bowl, sprinkle salt, add vinegar and half of the vindaloo paste, saving the rest for later. Toss the lamb pieces well to ensure they are evenly coated in the marinade. Cover, refrigerate and let marinate for 5-6 hours.

In a heavy bottomed pot, warm up the oil on medium heat. Temper the hot oil with black mustard seeds. Let the mustard seeds pop.

Add the chopped onions next and on medium heat, brown the onions for 5-6 minutes. Carefully, add the reserved vindaloo paste to the golden brown onions. Fry for 1-2 minutes.

Then add the marinated lamb to the pot. On medium-high heat, fry the lamb pieces, stirring intermittently, for about 8-10 minutes to sear them on all sides.

Scatter the fresh curry leaves over the browned lamb pieces and add in about ½ cup to ¾ cup of hot water. Cover the pot for about 1 to 1.5 hours and let simmer on low heat.

Once the lamb is quite tender, add in the jaggery and tamarind pulp and mix well. Cover again and let cook for about 5-10 minutes more until lamb is fully fork tender.

For Instant Pot, set to sauté mode, warm up the oil and fry up the onions. Add the reserved vindaloo paste and fry with onions. Add the marinated lamb and stir until browned on all sides. Pour in the hot water, secure the lid, and set the timer for 8-10 minutes.

Once the cooking time is up, let the pressure release naturally for about 10 minutes, then carefully turn the valve to release any remaining pressure. Open the lid, stir the curry, and taste for seasoning.