Place the flour for the dough in a mixing bowl and, using a fork, gradually stir in the measurement water until incorporated. Add more water if the mixture seems dry.
Transfer the dough to a clean work surface and knead for 8–10 minutes, dusting with a little flour if sticky. Return to the bowl, cover with a damp tea towel and leave to rest for 20 minutes.
Mix all the ingredients for the filling together in a separate bowl until well combined. Set aside.
Knead the dough again for 5–6 minutes until smooth, then shape into a roll about 23 cm (9 inches) long, 2.5 cm (1 inch) in diameter, then slice into 16 pieces. Roll each piece into a small ball, then roll out each ball into a 9 cm (3½ inch) 'pancake'. Cover them with a damp tea towel to prevent them from drying out. Place 2 teaspoons of filling in the centre of each 'pancake' and moisten the edges with water. Fold the dough in half to form a moon shape and pinch the edges together with your fingers. Pleat around the edge, pinching to seal well.
Heat the groundnut oil in a large, lidded nonstick frying pan until very hot and add the dumplings. Reduce the heat and cook for 2 minutes until lightly browned. Add the measurement water, cover the pan and simmer gently for 12–15 minutes, or until most of the liquid is absorbed. Check halfway through and add more water if necessary. Uncover and cook for a further 2–3 minutes. Serve with dark soy sauce and sweet chilli sauce for dipping.