Prepare the ingredients. Soak the dried chillies (guajillo/ cili merah besar and dried cayenne/ cili merah) in hot water for 20 minutes and drain the water.
Marinate the chicken pieces with 1/2 tbsp of salt in two parts, making sure to rotate them to spread the salt evenly. Set it aside.
Cut the soaked dried chillies (guajillo and cayenne) over a blender. Add the peeled shallots, chilli powder, curry powder for meat, and 400ml of diluted coconut milk. Blend until a wet paste is formed, and is even in colour. Set it aside.
In a large wok, add 3 tbsp of cooking oil over medium heat. Without waiting for the oil to become hot, give a quick rinse to the cinnamon sticks, cardamoms, and star anise, then add them to the wok. Strip the leaves from the curry leaves stems and briefly mix all the aromatics in the wok. Then, add the mixed spices (halba campur) and optionally, 1 tbsp of cooking oil if the aromatic mixture looks dry. Stir for about 1 minute, or until well combined and very fragrant.
Then, mix in the garlic and ginger paste to the aromatics in the wok, until well combined. Optionally, mix in another 1 tbsp of cooking oil if the aromatic mixture looks dry. Then, add all the blended curry paste, scraping the sides of the blender with a spatula. Mix consistently for 8-10 minutes, or until well combined.
After 4 minutes of stirring, reduce the heat. Swirl about 350ml of diluted coconut milk in the blender to get all the stuck curry paste.
Add the mixed coconut milk curry paste and sliced red onions to the wok. Continue stirring the paste constantly for the remaining minutes over medium heat or until well-combined and slightly dry.
When the 8-10 minutes are up, add the marinated chicken pieces to the wok, turning them for an even coating. Next, add the tamarind slices (asam keping), and concentrated tamarind juice. Carefully stir for about 3 minutes, or until well combined. Switch off the heat.
Carefully transfer the chicken curry to the instant pot, and top with potatoes, 1/2 tbsp of salt, sugar, 250ml of diluted coconut milk, and 150ml of coconut cream. Stir until combined. Close the lid, seal the pressure valve, and choose the "Chicken" setting, or let it cook for about 15 minutes.
Once done, carefully release the pressure valve. Once all the pressure has been released, open the lid. Immediately add the cut green chillies, tomato wedges, and 150ml of coconut cream. Stir and close the lid. Let it rest for about 10 minutes.
Open the lid, and dish out the chicken curry. Chop some cilantro and sprinkle as garnishing. Serve with some white rice.