Bánh bột lọc trần Huế (Vietnamese tapioca dumplings)

Mix the pork belly and shrimp separately with the fish sauce, sugar, pepper and shallot. Cover and refrigerate for 20 minutes. Heat annatto or neutral oil in a skillet. Use a clean thin-tip thermometer inserted from the side into the centre of the thickest 1 cm pork strip. Cook the pork to 63°C, then rest it for 3 minutes. Add the shrimp and cook until opaque and the thickest shrimp reaches 63°C. Cook off excess liquid, then cool the filling.

Stir fish sauce, warm water, sugar and lime juice until the sugar dissolves. Add garlic and optional chilli; set the nước chấm aside.

Put scallions and salt in a heatproof bowl. Heat 20 ml oil until shimmering but not smoking, pour it over the scallions and stir.

Place tapioca starch and salt in a heatproof bowl. Carefully pour in boiling water while stirring with a heatproof spatula. Add 5 ml oil and knead once cool enough to handle, about 2 minutes, until smooth and pliable. If dry crumbs remain, add only a few drops of hot water; if sticky, dust hands with a little extra starch. Cover and rest for 20 minutes.

Divide dough into 24 pieces and keep them covered. Roll each into a 7 cm round about 2 mm thick. Place a small portion of cooled filling in the middle, fold over and pinch the edges firmly to seal. Keep the seam clear of filling and arrange dumplings on a starch-dusted tray.

Bring a large pot of water to a steady boil. Cook dumplings in batches without crowding, stirring gently once. When they float, continue boiling for 2 minutes, until the wrappers are translucent and no opaque starch remains at the sealed edge. Lift with a slotted spoon into cool water for 30 seconds, drain, then toss gently with scallion oil. Serve with nước chấm.