To make the dough, combine the flour and water and knead for 10-15 minutes. Wrap the dough in cling wrap and leave for 5 minutes at room temperature.
To make the filling, combine all ingredients and mix well. Set aside.
Roll the dough into a long rope-like length (about 4 cm thick). Separate the length into about 20 sections, each section about 4 cm long. Using a small rolling pin, or by hand, roll out each section into a circle. Try leaving the dough thicker in the middle to create a base, and much thinner at the edges. The circles should be about 8-10cm across. (Note: This is the traditional Tibetan technique, but it's also possible to first roll out the entire dough and then cut out circles using the mouth of a large cup or pastry cutter.)
Take a circle of pastry in one hand, and with the other hand, add a tablespoon of the filling to the centre of the circle. Begin closing up the momo by making a series of pinches with thumb and forefinger, adding each pinch to the previous one, until the entire edge is gathered up into a pleat at the top. Finally, pinch and twist the pleat to seal the momo.
Place momos into a large steamer over boiling water. Space the momos apart so they do not stick together, and lightly oil the steamer first if stainless steel. Steam momos for 6-8 minutes.
Serve hot with sweet chilli sauce or soy sauce.
The filling is also yummy with added cheese or tofu.
Gluten-Free Option - There are some good all-purpose flour blends available from health food shops that are gluten-free and won't stick when steamed.