Sesame rice crackers (banh da vung)

Instructions

1. Step 1

   Put 400 g rice flour, 50 g tapioca starch, 15 g granulated sugar and 6 g salt in a bowl, gradually pour in 650 g water and stir until dissolved, then strain it through a sieve and let it rest for about an hour. A long rest makes the batter smoother, so the crackers don't crack as they dry. The batter is ready when it is as thick as rich soy milk and flows in an unbroken stream when you lift the ladle.

   Suggested time: about 60 minutes.

   Mark step 1 as done

2. Step 2

   Rinse 60 g black sesame seeds in water to remove any grit and empty husks, then drain them in a sieve. Clean, slightly damp sesame sticks firmly to the crackers and won't fall off while they dry. The sesame is ready when the seeds are glossy black, none are floating and they have drained well.

   Mark step 2 as done

3. Step 3

   Stretch a piece of thin cloth over the mouth of a pot and tie it so it is evenly taut, bring the water to a rolling boil, then brush a thin layer of vegetable oil (to taste) over the cloth and over the bamboo racks or trays you will use to dry the crackers. A flat, taut cloth gives evenly thick sheets, while the thin film of oil keeps them from sticking when you peel them off. The pot is ready when steam comes evenly through the whole surface of the cloth.

   High heat.

   Mark step 3 as done

4. Step 4

   Stir the batter again, pour a full ladle onto the cloth and swirl the bottom of the ladle to spread it into a round about two millimeters thick, sprinkle a pinch of sesame evenly over it, then cover for about two minutes. A layer thicker than soft rice sheets gives the dried crackers enough body to puff up when toasted. The sheet is cooked when it turns translucent, the sesame is stuck fast and the edges curl up slightly.

   Suggested time: about 2 minutes. High heat.

   Mark step 4 as done

5. Step 5

   Use a bamboo stick to peel off each sheet and lay it on an oiled rack or tray, then dry it in strong sun for one to two days, or in a 70 degree Celsius oven for about 150 to 210 minutes, turning halfway through. The crackers must be completely dry to puff when toasted; if they are still damp, they turn chewy and scorch. They are ready when they are as hard as plastic sheets, clack when tapped and snap crisply when bent.

   Bake at 70°C for about 150 to 210 minutes.

   Mark step 5 as done

6. Step 6

   Toast each cracker over glowing charcoal, turning it constantly with tongs, or microwave it on high for about one to two minutes. The heat turns the remaining moisture in the cracker into steam, which puffs it up into crisp bubbles. They are ready when they have grown to about one and a half times their size, are evenly puffed all over, ivory white and wonderfully fragrant with sesame.

   Suggested time: about 2 minutes.

   Mark step 6 as done