Prepare the marinade by blending lemongrass and galangal with water, then blend this liquid until smooth. Strain to remove any solid particles.
In a separate bowl, mix together chicken powder, cayenne powder, turmeric powder, sweet curry powder, white pepper powder, and salt.
Rub the spice mixture all over the chicken thighs, ensuring they are well coated. Add the strained lemongrass-galangal liquid and blend again to moisten the chicken.
Gently place the marinated chicken into a steamer basket or large pot with steam rising from boiling water for 20 minutes until cooked through. Remove once done and set aside.
Wash basmati rice thoroughly in cold water, then rinse with hot water several times to remove excess starch. Drain well and add sufficient water (usually about double the volume of rice) to a large pot or steamer basket. Cover and steam for 20-25 minutes until fluffy and fully cooked.
For the sambal belacan, mince one large onion with an inch of kaffir lime zest along with five garlic cloves. Sauté this mixture in oil with four spices (clove, cardamom, fennel, and star anise) for about 5 minutes until fragrant.
Add three teaspoons of dried red chili peppers, followed by three teaspoons of meat spice powder, two teaspoons of beef spice powder, and any remaining ingredients from the chicken marinade. Stir in coconut milk and cook for another 2-3 minutes before adding one small cube of palm sugar and adjusting seasoning with salt to taste.
Fry eight black peppercorns and ten dried shrimp paste until fragrant, then blend into a smooth paste using four cloves of garlic and five kaffir lime leaves. Add two teaspoons of sugar and a little bit of flavor enhancer if needed; blend in some water to form a smooth belacan sauce.
Once the rice is cooked, place it on individual plates or serving bowls. Arrange the steamed chicken on top of the rice with the gulai chicken broth underneath and garnish with a scoop of sambal belacan on top. Serve immediately for best flavor and texture.