Tentsuyu (天つゆ, tempura dipping sauce)

Ingredients

Equipment Needed

• •Small saucepan
• •Fine-mesh strainer lined with a clean cloth
• •Oroshigane (Japanese grater), or the fine holes of a box grater
• •Small dipping bowls

Instructions

1. 1

   Steep the konbu

   Wipe the konbu with a damp cloth, but don't wash it. Put it in 2 cups cold water and bring it up slowly over low heat, about 10 minutes. Pull the konbu when the water trembles and small bubbles climb the sides of the pot, before it boils. The white bloom on the kelp is flavor, and boiling the kelp pushes the stock toward bitterness and a slippery feel.

   You're steeping the konbu, not boiling it. That one quiet decision protects the clarity of the whole sauce.
2. 2

   Add the flakes

   Bring the water to a gentle boil, add the katsuobushi all at once, then immediately turn off the heat. Let the flakes sink for 2 to 3 minutes without stirring. They give their aroma quickly, and stirring only roughens a stock you want clear.

3. 3

   Strain the dashi

   Strain the dashi through a cloth-lined sieve and let it drip on its own. Don't squeeze. Squeezing presses strong, oily flavors from the flakes into the clear stock, which is exactly what we are trying not to do. Measure 1 1/2 cups dashi for the sauce and keep any extra for soup or a small simmered dish.

4. 4

   Warm the sauce

   Put the mirin in a small saucepan and bring it to a quiet simmer for 45 to 60 seconds. This sends off the raw alcohol and leaves the round sweetness behind. Add 1 1/2 cups dashi and the shōyu, then warm just until tiny bubbles gather at the edge. Do not reduce it; tentsuyu should taste like seasoned dashi, not a salty glaze.

   The balance is about 4 parts dashi to 1 part mirin and 1 part soy. The dashi leads, and the seasonings give it shape.
5. 5

   Serve with daikon

   Peel and grate the daikon on an oroshigane, a Japanese grater, or use the fine holes of a box grater. Drain it lightly, but don't wring it dry; that fresh juice is part of how it lifts the oil on the tongue. Pour the warm tentsuyu into small bowls and add a spoonful of daikon to each, or serve it beside the sauce. Dip tempura briefly, just enough to season the edge.

Chef Tips

• •Use hon mirin if you can. Mirin-style condiments are sweeter and thinner in aroma; if that's all on your shelf, use 4 tablespoons and know that it is a stand-in.
• •Grate the daikon just before serving. It loses its clean edge as it sits, and that edge is why we invite it to the bowl in the first place.
• •For a meatless table, make the stock with 6g konbu and 2 dried shiitake soaked overnight in 2 cups water, then warmed gently and strained. That is the way the temple kitchens do it, honmono in its own right.
• •Serve tentsuyu warm, not fiercely hot. Hard boiling dulls the soy aroma, and a very hot dip softens the batter faster.

Advance Preparation

• •The dashi can be made up to 2 days ahead and kept refrigerated. Warm it gently before making the sauce.
• •Finished tentsuyu keeps 3 days refrigerated. Reheat it quietly, without a hard boil.
• •Do not grate the daikon ahead. Prepare it at the table or just before serving so it stays fresh and bright.

Frequently Asked Questions

Nutrition Information

1 serving (about 175g)