One of the goals Bird and I are working towards is to come up with new dishes that are identifiably and uncompromisingly Vietnamese. Having availed ourselves fully of modern material culture, we still want the lineage of our dishes to be apparent, and the appeal of our recipes to mirror that of the recipes that inspired them. This is one of our successes:
The Vietnamese inspiration for this dish was chè trôi nước aka chè xôi nước, bánh trôi nước, or bánh trôi bánh chay. Briefly: it’s a dessert of glutinous rice dumplings with or without mung bean paste filling, floating (trôi) in a strong gingery sweet syrup. The other inspiration was Thomas Keller’s fake egg yolks (encapsulated mango juice) for his vegetarian steak tartare. The third element came from a variant recipe for bánh trôi nước using khoai môn (taro) to make the glutinous outside purple. Putting it all together we get the above picture.
Our version of chè trôi nước is encapsulated mung bean milk and purple sweet potato puree. The encapsulation is done via reverse spherification: Calcium lactate and calcium gluconate is dissolved into the liquid to be encapsulated at 2% while sodium alginate is dissolved into a water bath at 1%. Sodium alginate is a substance extracted from seaweed that remains liquid until crosslinked into a gel by calcium. When mung bean milk or sweet potato puree is dropped into the alginate bath the calcium reacts with the alginate to form a gel coat around the milk/puree. The spheres are stored in a different water bath containing 8% sugar (roughly the amount added to sweeten the milk/puree) to prevent diffusion of water changing the content of the spheres. Before serving the spheres are placed in a bowl of hot (temperature wise) and spicy ginger syrup and drizzled with coconut milk. The spheres are the reason why we took off the diacritical mark from bánh (cake) to form the word banh (ball).
We were excited to serve this dish as our featured dessert during the Tết season and were happy to see it produce just as much excitement with our friends and our parents and their friends. People loved the fact that the spheres popped in their mouths. My friends in particular were reduced to the level of giggling high school stoners. Many noted the interesting contrast between the cool and almost savory liquid inside and the hot and spicy gingery syrup outside. It’s a neat effect we didn’t design for, but we’ll take credit for it. Now I can’t wait to make this dish for my grandmother, who introduced and made it for me when I was little.