One of the most origins of Cốm can be traced to Vòng village, 7 km west of Hanoi downtown. The legend begins with a severe starvation in the village years ago. Since the rice crop was not ready for harvest, residents then had nothing else to eat. One hungry farmer tried roasting the unripe grains of rice as his last resort. Just like the accidental invention of Cocacola in the West, Vong villagers found that by roasting the rice in a clay jar and smashing it to remove the husks, they could produce a delicious dish, called Cốm. As the rumors about the new dish spread widely, the King sent for the head villager of Vòng to the court. The King was so delighted with this dish that thereafter, each autumn, Vòng villagers were requested to present him with their Cốm.
The making of Cốm is still kept as a family secret. What most people know is that the process of making Cốm is complicated and tedious. The main ingredient is young glutinous rice, carefully selected since they are in their blossom. The grain must be manually threshed and cleaned, before being roasted with a stoneware pan over firewood. The fire is kept low and steady and the cooking process need full attention. For flavor and color preserving purpose, each batch should comprise 800 grams of rice at the maximum. The dried grains are then pounded in a mortar and stirred frequently from bottom to top. This step is repeated 7-8 times to remove all the husks from the grains. The final result is glossy green rice, soft and slightly chewy, that is nowhere to be found.
Cốm is normally eaten by hand, a pinch at a time, or served with red persimmons and ripe bananas. Chewing Cốm slowly is the way to enjoy its subtle scents, tastes and softness. One note is that Cốm should be eaten within 24 hours or its original taste will be lost.
Due to the short season, Cốm is used to make many other Vietnamese specialties to relieve people’s craving in other months. Examples of derivatives from Cốm is Cốm xào (stir-fried green rice), Cốm rang (puffy green rice that resembles rice krispie), Bánh cốm (green rice cake- a must for Vietnamese engagement ceremonies), Kem Cốm (ice-cream with Cốm flavor) and Chè cốm (sweetened green rice paste), etc. Many worth-trying dishes involving Cốm are chicken stewed with herbs and green rice, or fried shrimp coated in Cốm.