
I think the light herby-bitterness of the grass jelly cuts through the richness of the soy milk. As far as I know all grass jelly products (usually sold in cans) taste the same. But soy milk may vary in flavor depending on manufacturer, and whether it has been sweetened or flavored. Use whatever you like.
I just thought I'd post this so there will be something to wash down the spicy Thai Chicken Basil Stir-fry.