Make the soy bean paste the day before you plan on cooking this dish, or at least a few hours in advance. Put the fermented black soy beans into a food processor or blender with the onion, garlic, sugar and salt and add 50ml water. Blend until you have a thick, smoothish paste. Scrape into a bowl and mix in the sesame seeds, then refrigerate for a few hours or preferably overnight to allow the flavours to meld.
When you are ready to make the dish, dust the chicken pieces with the po