1 lb. Chinese yam
5 oz. potato
5 oz. sugar
8 oz. haw jelly
1) Wash and peel yam and potato.
Crush haw jelly into mash.
2) Steam yam and potato to cover on high flame for 40 minutes till very soft. Cool, then crush into mash and mix well.
3) Divide yam-and-potato mash into three equal parts and haw jelly mash into two parts.
Spread on a plate one portion of yam mash in the form of a rectangle or a disc. Spread on a layer of haw jelly, then follow with a second layer of yam mash, another layer of haw jelly, and then the third and last layer of yam mash - totalling five layers about 1.1/2 inches thick. Sprinkle on sugar to serve.
(1) The moisture content in raw yam and potato may vary to some extent. If their mash is too thin, mix in some wheat flour, pre-steamed, to make it firm and easy to shape. If the mash is too dry, some, sugar rubbed in will make it softer.
((2) Any other filling suitable for sweet cake may be used instead of haw jelly, according to eating habit and availability. Other possibilities in China include sweetened bean paste, jujube paste, lotus seed mash, and what not.
(3) This cake may be made in another shape: Spread yam-and-potato mash into a rectangle of even thickness. Shape the filling into a strip and put it close to one end of the rectangle. Carefully roll this with the filling inside into a roll. Before serving, cut into thick slices holding knife at an angle, arrange in serving dish and sprinkle on sugar. The sugar may be rubbed in with some mash of osmanthus flowers for a blended fragrance.