Tempura is a Japanese dish of battered and deep-fried vegetables and seafood. Common ingredients to fry are shrimp, squid, green bell pepper, eggplant, sweet potatoes, potatoes, kabocha, carrot, mushrooms, and shiso (perilla). Tempura is best served hot with salt or tempura dipping sauce and is often garnished with grated daikon radish.
Many of the ingredients to make tempura can easily be found at your local grocery store. The trick to perfect crispy tempura is to get the batter as light as possible. If you follow a few tips it's pretty easy to make delicious restaurant-quality tempura in your own kitchen.
Making the Batter
If you make battered fried food often enough, you are aware there are good recipes and methods and there are others that end with heavy, oily results. So when it comes to tempura, following a few tricks when making the batter will ensure success. First, make sure you use cold or ice water; this is important to prevent the batter from absorbing too much oil. You also want to use cake flour instead of all-purpose flour; the lower content of protein helps minimize the formation of gluten in the batter which prevents a bready crust.
When combining the ingredients, do not over mix the batter; you actually want it to be somewhat lumpy. Using a few chopsticks in a kind of stabbing motion will help combine the ingredients without mixing them too much. Definitely, do not use a whisk; this will activate the glutens and create a chewy coating. And do not prepare the batter ahead of time—it is better to make the batter right before frying tempura.
Lightly coat the seafood or vegetable in the cake flour before dredging in the batter. This allows the batter to adhere better. Another tip to keep in mind is to be somewhat minimal when coating the ingredients with batter. If there is too much batter, the outside might be crispy but the inside could be mushy.
One of the most important things when deep frying is the temperature of the oil. The right temperature to fry tempura is around 340 F to 360 F. If you don't have a deep-fry (or candy) thermometer, check the temperature by dropping a little bit of batter into the oil; if the batter comes up right away instead of sinking to the bottom of the pan, it's higher than 370 F and too hot. If the batter goes halfway to the bottom and comes up, it's just right, about 340 to 360 F.
When adding food to hot oil the temperature of the oil drops, so make sure you maintain the oil temperature by raising the heat when needed—or lowering it if the oil gets too hot. If the temperature is not hot enough the batter will absorb too much oil and won't get crispy; if the oil is too hot, the tempura will burn. The tempura should be surrounded by bubbles as it cooks; as the bubbles get larger it means it is almost done cooking. Most ingredients only need 2 to 3 minutes a side.
If you are frying both seafood and vegetables, fry the vegetables first, then fry the seafood. As the tempura cooks, drizzle some batter (using your fingers) over each—this is called hana o sakaseru and makes the tempura even crispier. (You can remove any stray fried batter with a slotted spoon and serve on top of salad or noodle dishes.)