Sweet potato tempura is a popular, affordable, batter-fried delicacy that is often found at sushi restaurants but also can be made at home. This deep-fried appetizer is believed to have originated in the late 16th century among Spanish and Portuguese settlers in Japan. It is crisp and light flavored yet not too greasy. Sweet potato tempura is often served with a dipping sauce along with other tempura-coated vegetables, including eggplant, lotus root, mushrooms and carrots, as well as with tempura shrimp, squid and other seafood. Although it is good on its own, tempura is also delicious in sushi rolls.
Diced pieces of deep-fried yam tempura wrapped in sticky rice and seaweed are used to make sweet potato tempura sushi rolls. The salty seaweed and the subtly sweet flavor of the sweet potato tempura combine with the unique textures of the sticky rice and crunchy tempura batter. This create a succulent and frequently raved-about sushi dish.
Although it is possible to make tempura batter at home, recipes must be precisely followed to ensure restaurant-quality tempura. Tempura batter is generally made of flour, baking powder, salt, beaten eggs, milk and vegetable oil. Cake or pastry flour can be substituted for a lighter batter. Along with these ingredients, making tempura requires mixing bowls, a deep frying pan, a whisk, metal cooking chopsticks, utensils and a pan filled with ice water in which to keep the batter. Light-colored beer can be substituted for the water for added flavor and coloring.
After the sweet potato slices are slightly heated and sprinkled with flour, they should be dipped one by one into the tempura batter and fried to a light golden crisp in the oil that is heated to 350 degrees Fahrenheit (176.7 degrees Celsius). As long as the batter has been kept cold before frying and the oil is kept clean, the sweet potato tempura should come out the perfect color and texture. It is recommended that the batter not be thoroughly mixed, because a lumpy tempura batter makes it easier to achieve the desired effect. The chopsticks can be used to fold the batter to obtain the perfect lacy consistency.
The tasty tempura dipping sauce served along with sweet potato tempura generally consists of soy sauce, dashi, mirin and freshly grated ginger and radish boiled together. Although the origin of tempura should not be forgotten, it was the Japanese who created this lightly seasoned dipping sauce for sweet potato tempura sushi. This is one reason why it is a favorite at sushi restaurants worldwide.