What is tempura? Thanks to Japanese cuisine's meticulous preparation and fabulous, eye-catching presentation—think of the kaleidoscope of fish and vegetables inside every slice of a sushi roll—maki gets most of the attention. But for a dish with a different type of decadence, turn to tempura batter, which gives a crispy, uniquely flaky finish to veggies and seafood.

What is tempura made out of?

A batter that puffs up into an airy, golden crunch in the deep fryer, tempura is simply a mixture of water, flour, and sometimes egg. Naturally, that short ingredient list is what forces chefs to become so compulsive about getting it right.

Rice flour can provide a delicate crispiness; wheat flour has a stronger flavor but must be carefully mixed to keep it from becoming too dense and glutinous. Using ice-cold water also prevents gluten strings from forming, and some chefs even substitute sparkling water—its bubbles add extra air to the batter.

And when it comes to what to batter, traditionally chefs give the tempura treatment to seafood—shrimp, squid, some kinds of fish—as well as sturdier veggies, such as eggplant, bell peppers, squash, and sweet potatoes, making even the most difficult-to-love veggies delicious. Some chefs batter entire maki rolls in tempura, blending two traditional dishes.

When was it invented?

Tempura is a mainstay of many Japanese restaurants, but its roots aren't as ancient as those of sushi or teriyaki. Animal fats were rare in early Japan, and vegetable oils were used primarily for fuel, so frying took a while to catch on. Many theorize that it was finally introduced in the 16th century by Spanish and Portuguese traders and missionaries, after which a throng of tempura-fried fish vendors popped up in the streets where Tokyo now stands.