By Steve Sumida
Pre-mixed, packaged tempura flours have made this watercress tempura easy to make. It may be that our Issei great grandmother was the first to make watercress tempura since there was little or no watercress in Japan at that time, the early-20th century. The Hawai‘i Issei—that first, immigrant generation—called the watercress in Hawai‘i “seri,” the name of a different vegetable that grows in fresh water, common in Japan and Korea.
Sumida Obaachan helped to make watercress known, to where, by consulting us at Sumida Farm in the 1960s, agricultural scientists and entrepreneurs in Japan introduced it there by the French name “cresson.” Obaachan would demonstrate how to make her watercress tempura on early TV shows in Hawai‘i, like the weekly Japanese program, “Terebi Digest.” The tempura caught on.
Two generations later, David Sumida made watercress tempura many times on TV shows, using and revising Obaachan’s recipe.
- 1 bunch of Sumida Farm watercress
- 1 ½ cup of tempura-ko (powder, flour), such as Kikkoman Tempura Batter Mix in a 10-oz. box or Welna brand in a 600-gram plastic bag, from Japan
- Enough cold water or cold unflavored sparkling or soda water, starting with about ½ cup, to mix with tempura flour and make a slurry for tempura vegetables
Whisk together the tempura flour and the cold water. The slurry for tempura watercress and many other vegetables should be thin, not like a pancake batter, so that the watercress ends up crisp and light. Whisk lightly, leaving some small lumps to give texture to the tempura. The ready-mixed flour already contains the necessary starches, leavening, and baking soda.
Cut the watercress into four-inch lengths. Mix together the stem and leaf as desired, and put them into the batter.
Heat the oil in a wok or pan for deep frying, to 375 F. degrees. A drop of batter should immediately sizzle, fry, and rise to the surface when the oil is hot enough.
Drop the battered watercress, a couple of tablespoons at a time and without crowding the pan, into the hot oil. Deep fry until it’s light golden and crisp.
Serve with a tsuyu (thin sauce of dashi, mirin, and shoyu) or other sauce you may prefer.
Note: this tempura batter and method can be used for other vegetables, while you’re at it: thin crescents of kabocha, slivered green beans, sliced renkon, whole, small, fresh shiitake mushrooms, sliced eggplant, or shiso, or nori, for example.