Now that summer's coming soon to a neighborhood near you (at least in the Northern Hemisphere), you have to keep this simple but magical technique — ohitashi — in mind. Ohitashi is a method of steeping vegetables in a delicate dashi, which infuses ingredients with umami and lovely flavor but retains the food's natural taste and sensibility. The trick is to first blanch and shock the vegetables (quickly boiling in water, "blanching," then halting the cooking by plunging in ice-water, a.k.a. "shocking"). By partially cooking this way, you transform ingredients from the raw state, but still retain their integrity, and allow them to absorb the dashi.
In his class last week, Atsushi Nakahigashi selected spring veggies for this dish, but ohitashi is super versatile, and you can prepare it with green beans, spinach, shishito peppers, broccoli, snap peas, sugar peas, cherry tomatoes, all kinds of mushrooms, eggplant and more (for tomatoes and eggplants, instead of blanching and shocking, you quickly deep fry to partially cook them; see this post). So go to town this summer — or all year round, actually. Here's Atsushi's method, for four:
- 3 large spears asparagus (about 2.5 ounces)
- 1 large shiitake mushroom (about 2.5 ounces)
- 8 snap peas (about 1.25 ounces), ends trimmed
- 4 cipollini onions (about 2 ounces), skins removed
- 8 fiddlehead ferns (about 1.5 ounces), cleaned
- 1 cup dashi
- 1 1/2 tablespoons usukuchi soy sauce
- 1/4 teaspoons salt
- Pinch sugar
1. Use a peeler to remove skin from the bottom half of each asparagus spear, and cut into bite-size pieces.
2. Rinse the shiitake, remove stem, and cut notches at the base where the stem was, so it cooks uniformly. Lightly sprinkle salt on the shiitake's cap, wrap in foil and place on a wire grid or skillet over medium-low heat. Cook until the mushroom is soft and you see liquid bubbling out of the foil, about 10 minutes. Cut the mushroom into eights and set aside.
3. Combine the dashi, soy sauce, salt and sugar in a saucepan and bring to a boil over high heat. As soon as the liquid boils, turn off the heat. Transfer to a mixing bowl and cool in an ice bath, or place in the refrigerator for 20 minutes, or until cool.
4. Bring a large pot of water to a boil, and blanch and shock the vegetables in batches: about 30 seconds for the peas and asparagus, about 5 minutes for the ferns and onions.
5. Add the vegetables and mushroom pieces to the dashi and steep for at least 30 minutes to 1 hour in the refrigerator.
6. Serve the vegetables cold, with about 1 tablespoon of the dashi.