Don't be tempted to use curry powder to cook rendang. Substituting commercial curry powder or paste for the rendang spice paste will not give the dish the flavors of real rendang.
In an oil-free pan, toast the garlic, chilies, coriander seeds, peppercorns, shallots, turmeric and cumin seeds.
Transfer to a blender, add the crushed galangal and nutmeg. Process with a couple of tablespoonfuls of water to form a paste.
Marinate the pork
Place the pork in a shallow bowl.
Pour in the spice paste.
Mix and work the spice paste into the meat.
Cover and keep overnight in the fridge.
Cook the rendang
Heat the cooking oil in a thick-bottomed pan.
Saute the chopped onion, lemongrass and cinnamon sticks.
Add the pork to the hot oil and cook until lightly browned along the edges.
Add the kaffir lime leaves.
Pour in the coconut milk and tamarind extract.
Add the desiccated coconut. Stir.
Season with fish sauce and sugar.
Cover and simmer for an hour to an hour and a half (or longer) or until the pork is tender. Stir occasionally and remember to scrape the bottom of the pan. Taste occasionally as well and add more fish sauce or sugar, or both, as needed.
Uncover the pan. Add half of the sliced scallions. Turn up the heat and continue cooking, stirring and scraping the bottom of the pan often, until the pork rendang is dry.
Serve the pork rendang with more sliced scallions over hot rice.