Makes 2 Servings
2 1/2 cups cake flour, divided
2 egg yolks
2 cups cold water
1/4 cup ice cubes
1/2 pound fish, cut into 1-inch cubes
4-6 shrimp, peeled and deveined
1 small sweet potato, peeled and thinly sliced
1 small zucchini, thinly sliced
1/4 cup toasted sesame oil
Fill a deep cast-iron skillet with enough canola oil to a depth of at least one inch. Heat the oil over medium heat to 360 degrees, checking it with a deep-fry thermometer placed in the skillet. Maintaining a consistent temperature is important to creating the perfect color and crispness of the batter.
While the oil is heating, place one-half cup of the cake flour on a plate for dredging and line a sheet pan with paper towels for draining; set both aside. Place the two egg yolks in a medium sized mixing bowl.
Mix the yolks with two cups of cold water. Add 1/4 cup of ice cubes. (Keeping the liquid ice cold will reduce gluten development in the batter.)
Add 2 cups of cake flour. Grasping four chopsticks, their tips pointed down, stab at the flour to combine it with the liquid until a loose, lumpy batter forms, about thirty seconds. Do not whisk, and do not use a fork; you want the batter to be barely mixed, so as not to activate the glutens. Pockets of dry flour should be visible in the liquid, which should have the consistency of heavy cream. (Mix the batter just before cooking, so the flour particles have limited time to absorb moisture.)
To cook, start with the fish and then the shrimp. Lightly dredge them in the flour This will help the batter adhere.
Dip them quickly into the batter. If the batter appears watery, sprinkle a little flour on top, but do not mix it in; dipping the ingredients in the batter will be enough to combine the flour with the liquid.
Just before frying, add the toasted sesame oil to the frying oil. If the oil temperature lowers, allow it to rise back to 360. Quickly lay the fish in the oil; separate them from one another with chopsticks. Cook the fish until the bubbles around them grow larger and less intense, and the batter turns golden brown, about three minutes. Remove the fish from the oil, and place them on the paper towels to drain. Sprinkle with a little salt if desired while warm. Follow the same procedure for the shrimp.
To maintain consistent oil temperature, cook the rest of the ingredients in small batches. Cook vegetables at 350 degrees about 2 1/2 minutes for most.
Serve the tempura immediately, with a dipping sauce or seasoned salt.
Slightly adapted from Saveur, December 2012