Pork in Hot and Spicy Cayenne Sauce (Vindaloo)

1 1/2 pounds boneless pork shoulder or leg
For the marinade:
1 tablespoon coriander seeds
1 teaspoon cumin seeds
2 teaspoons mustard seeds
10 dry red chili peppers
1 teaspoon turmeric
1/3 cup coconut or red wine vinegar
1 tablespoon minced garlic
5 tablespoons mustard oil or olive oil
1 3inch stick cinnamon
6 whole cloves
1 cup finely chopped onions
1 tablespoon grated or crushed fresh ginger
1 tablespoon paprika
1 teaspoon Goan palm sugar or jaggery or maple syrup
1 cup water
Coarse salt

Trim all visible fat off the pork and cut into 1-inch cubes and place in a bowl. Combine coriander, cumin, mustard, and chilies and grind into a fine powder and transfer into a measuring cup. Add turmeric, vinegar, and garlic and mix. Pour the marinade over the pork and rub well. Cover and refrigerate overnight. Heat the oil in a large heavy-bottomed pan over medium/high heat until hot. Add the cinnamon, cloves, and onions, and ginger. Cook until the onions are very soft - do not let them brown - about 5 minutes. Remove pork from the refrigerator and drain, reserving the liquid. Add pork to the onion mixture and cook until the meat is lightly seared. Add paprika, plam sugar, water, salt, and the reserved liquid and bring the contents to a boil. Simmer pork for 1 1/2 hours or until very tender. Serve vindaloo with plain or coconut rice.