Rinse mung bean and soak in water overnight
Lay cheesecloth in steamer, pour mung bean over the cheesecloth, steam for 50 minutes
Pour steamed mung bean to Vitamix (or other blender), add water, 1 tablespoon at a time, enough for the Vitamix to blend the bean to fine paste. Do not over water.
If you are afraid the paste is not fine enough, this is a good time to press the paste through strainer.
Over low to medium heat, melt butter with vegetable oil, stir in mung bean paste and continue folding to avoid any burning. When oil is absorbed into the paste, add sugar and maltose. Continue to fold till it forms a nice dough.
Cool down the paste. Add any other ingredients and shape as desired.