Grind white peppercorns and coriander seeds into a powder using a mortar and pestle or a coffee grinder. Add lemongrass and garlic and pound into a fine paste. Transfer into a bowl and add all remaining marinade ingredients; stir to dissolve the sugar.

Split the breasts in half so you have two split, bone-in breasts (see technique in the video) and separate the dums from the thighs. Trim off excess skin from the thighs, if any.

Add chicken pieces to a zip-top bag or a casserole dish and pour the marinade over, making sure all the pieces are well coated. Press out as much air as possible and marinade for at least 2 hours or overnight, stir the chicken or flip the bag half way through to ensure even marinating.

Make the toasted rice powder by adding raw jasmine or glutinous rice into a dry skillet, then toast over high heat, stirring constantly, until the grains are dark brown. Remove from heat and pour the rice onto a plate to cool slightly. Once cool, grind in a coffee grinder or mortar and pestle into a powder.

Combine the tamarind, fish sauce, lime juice and palm sugar; stir until the sugar is dissolved (it will really help to make sure your sugar is very finely chopped prior to mixing).

Add the chili flakes and shallots. Close to serving time, stir in the green onions, cilantro and toasted rice powder.

About 45 minutes before cooking, pull the chicken out to room temperature so they're not too cold.

Preheat the grill on medium heat, then place the chicken on the grill, skin-side up. Tip: If your grill has hot spots and cool spots, place the chicken on the cool spots to prevent the skin from burning, and you can move them to the hot spots later if more skin charring is desired.

Turn the heat down to low or medium-low and cook with the lid closed, flipping every 5 minutes, until done, about 18-30 minutes depending on the size of the pieces. If you've got large pieces of chicken, keep the BBQ temperature between 275°F - 300°F so the outside doesn't burn too quickly.

To check doneness, I highly recommend a good meat thermometer. Cook the chicken breast until the internal temperature reaches 160 °F or 72°C, and cook chicken drums and thighs until internal temp of 175°F (80°C).