Cut bean milk skin into large pieces.
Cut spring onions lengthwise then crosswise into sections.
Heat 2 cups of water in a pan, add onion and ginger, bring to a boil.
Cool and keep aside.
Soak bean milk skins for 1/2 hour in onion and ginger water, pressure cook and drain well.
In a bowl mix cooking wine, soya sauce, groundnut powder, sesame oil, five spice powder, salt and sugar.
Make a sauce.
Put this spicy sauce over bean milk skins and spread well, until well seasoned.
Spread muslin cloth over a board, arrange the well seasoned bean milk skins on one end of the cloth.
Place crushed walnut in the middle of the skins (make a straight line) leaving a loose end of about 4 inches on either side of the muslin.
Press hard with the help of the cloth.
Roll the skin with crushed walnuts forward into a complete roll (be sure not to roll in muslin) then fold over the loose ends and edges of the muslin.
Tie up this roll with a string, twining around closely and tightly.
Place in a pan, cover the roll, leaving enough space to swell.
Steam this roll over high heat, for 40 minutes.
Remove and cool.
Untie string, take off the muslin.
Brush with sesame oil to prevent drying.
Before serving, halve it lengthwise, then cut into slices, use as required.
Note: Vegetarian ham is one of the exotic Mock Meat dishes served in Vegetarian (Buddhist) restaurants seen all over Hong-Kong, Kowloon and Singapore. They display such beautifully made mock meat dishes, it is sometime difficult to believe one's own eyes.