If using savory filling, combine all the ingredients and then divide into 12 pieces of 30-gram dough ball. Do the same if you use red bean paste. Cover and keep them chilled in the fridge when you prepare the dough
If using mugwort or spinach leaves:
Rinse the mugwort or spinach leaves. Bring a large pot of water to a boil. Add the leave and blanch for 5 minutes. Submerge in ice-cold water then squeeze out the water. Put in a blender with 150 gr of water and blend into a paste. Transfer to a cheesecloth or a strainer and squeeze out the juice and discard the solid. Measure out 150 gr of the juice. You won't need all of the juice but we want to have a bit extra for adjustment in case we need it
Prepare the dough:
Combine wheatgrass powder/barley grass powder (if not using fresh mugwort/spinach), wheat starch, glutinous rice flour, and sugar in a large mixing bowl. Whisk to combine
Put 150 gr of the water/juice in a saucepan. Cover and bring to a rolling boil. Immediately pour 125 gr of this into the flour mixture. Keep the extra on the side in case you need it
Use a chopstick to stir at first, since it is still very hot. Stir quickly into a crumbly dough and then use your hand to knead into a rough dough. If it's too dry to even form a rough dough, you can add a bit more of the water/juice. Remember we haven't add the lard/shortening yet. So don't add too much liquid. As long as it can form a rough dough that won't fall apart. Add the lard/shortening and continue to knead into a smooth flexible dough
Filling and wrapping:
Divide the dough into 12 pieces, or roughly about 30 grams each. Roll into round balls. Keep them covered tightly and work with one dough at a time
Prepare your steamer by filling it up with water. Keep the water simmering on medium heat while wrapping. Line your bamboo steamer with parchment paper or lightly oil your steaming plate with a bit of oil
Use your thumb to push into the middle of the dough to make a deep "bowl" like shape. Put one filling inside and mold the dough gently to enclose it. Roll it round. If the dough gets a bit dry, you can wet your palms with some water and roll into a smooth ball
Put these on the prepared bamboo steamer or steaming plate, giving them about 1 -inch gap as they will expand a bit during steaming
Steaming:
Put the bamboo steamer or the steaming plate in the steamer and steam for 10 minutes over medium heat
When they are done steaming, immediately brush with thin layer of oil all over. They can be served warm or at room temperature
Storing:
Once they have cooled down completely, wrap them individually with a cling wrap to preserve the softness. They can be kept at room temperature for a day or two if it's not humid where you are, otherwise, keep them in an air-tight container and keep in the fridge for 3-4 days in the freezer for up to one month
Reheating:
If they have been kept in the fridge or frozen, reheat by steaming again over medium heat until they are warm, about 2-3 minutes. You don't need to thaw if frozen, just add few extra 3-4 minutes to steaming time