Pork: Combine pork belly ingredients and mix well to coat evenly with the marinade. Cover and marinate overnight in the refrigerator. Stir the pork belly one or twice if possible so that the meat marinates evenly.
Mushroom: Soak mushrooms with enough water to cover until softened. Trim off the stems. Cut into half or quarters if they are large mushrooms. Continue to soak the mushrooms overnight in the refrigerator.
Shrimp: Soak shrimps with enough water to cover. Chill in the refrigerator overnight.
Shallots: Peel and thinly slice the shallots. Divide into 6 portions.
Bamboo Leaves: Rinse the bamboo leaves and bamboo twine. Place in a large clean bowl (or in a cleaned sink) and submerge them completely under boiling water overnight. Use a pestle and mortar (or a heavy glass bowl of water) to keep the leaves submerged if needed.
Rice: Rinse glutinous rice several times until the water is translucent - about 5 to 6 times. Soak in water for 1 hour, then drain well.
Drain and squeeze dry the mushrooms and dried shrimps to remove excess water. Reserve 100g of mushroom water for the pork belly.
Mushrooms: Heat wok over medium-high heat and add in 1 portion of shallots. Cook until shallots are golden and add in the mushrooms.
Lower heat to medium-low. Cook, stirring frequently, until mushrooms are fragrant. Remove mushrooms into a bowl. (No need to clean the wok.)
Shrimps: Heat wok over low heat and add in a little oil and shrimps. Cook over low heat until the shrimps are fragrant - you can tell they are ready when they start to spit and sputter ("piak").
Add a little dark soy sauce to colour the shrimps. Remove the shrimps into a bowl and clean the wok.
Pork: Heat wok over medium-high heat and add in 1 portion of shallots. Cook until shallots are golden and add in pork belly, reserving the marinade.
Stir-fry until meat is cooked on the outside. Add in the cooked mushrooms, reserved marinade and reserved mushroom soaking water. Cook over medium heat until water has been absorbed, stirring frequently. Remove pork and mushrooms into a bowl and clean the wok.
Rice: Heat wok over medium-high heat and add in 20 tablespoon oil and remaining 4 portions of shallots. Cook until shallots are golden and add in salt.
Lower heat to low and add in drained rice. Toss to coat rice with oil and add in all the rice seasoning. Toss to coat rice evenly with seasoning. Remove from heat and transfer rice into a large bowl. There is no need to cook the rice for long as you want the rice to be loose (not sticky) for wrapping. If your wok is too small, cook the rice in batches.
Bamboo Leaves: Use a pair of kitchen scissors to trim off the head and tail of the softened bamboo leaves. Discard leaves that are badly damaged (e.g. with large holes in the middle). Shake off excess water and set aside for wrapping. The leaves should be kept moist. If they dry out, the leaves may crack when wrapping.
Rinse the bamboo twine and secure it on a rod or hook (I use the drying rack for my clothes).
Wrap: Use two bamboo leaves to form a cone. Fill the cone with rice, shrimps, pork belly, mushrooms, chestnut and end with rice. Secure with bamboo twine.
Pressure Cook: Fill 6-quart pressure cooker with bak changs and submerge them completely with boiling water. Add in 1 tablespoon salt. Pressure cook on high for 45 minutes. Rest for 5 minutes and force release the pressure. For subsequent batches, top up with water and add in 1 teaspoon salt.
Storage: Let the bak changs cool completely on a wire rack before storing in the refrigerator or freezer.
Reheat: Steam for 10 minutes (refrigerator) / 20 minutes (freezer) until heated through.
Do read the entire blog post for my own tips and notes.