Steam pumpkin until soft, then mash, cube or puree it.
Cut yam into thick slices and steam over high heat for approximately 20 minutes, or cooked through.
In an electric blender, liquidise steamed yam with water. Sieve.
Split gingkoes and remove the bitter-tasting plumule. Place gingkoes, sugar and water to cover in a small pot and boil over low heat until water dries up and gingkoes turn a shiny yellow.
In a pan, heat oil and fry shallots to make shallot oil. Remove shallot crisps for other use.
Add sugar and salt to the shallot oil in the pan. Stir slowly over very low fire and at the same time add the yam puree. You may add a little oil from the edge of the pan so that the yam paste will not stick to the pan.
Continue stirring until thoroughly mixed, about 20 minutes.
Dish out onto a shallow dish or individual moulds.
Top with the pumpkin and gingkoes. Serve warm.
Lotus Root Sauce: Mix the lotus root powder or cornflour and water. Place in a pan with the sugar and boil until it thickens. Pour onto the yam pudding to enhance its smoothness.
Note: LEE WENG ENG is a Teochew and owner-chef of the New Formosa Restaurant. Trained in Taiwan and Hong Kong, he specialises in Teochew, Sichuan and Taiwanese cuisine.