Golden oyster tempura.

Tempura is not a thick batter and it is not a crunchy one — it is a brittle, lacy shell that shatters. Three things get you there: an ice-cold batter, minimal mixing, and oil at exactly 340–350°F.

Golden oyster is the ideal candidate because the caps are thin and cook through in the same 90 seconds the batter takes to set. A thicker mushroom needs longer and the batter overcooks waiting for it.

What you need

Mushrooms

• 8 oz golden oyster mushrooms, separated into small bouquets
• 2 tbsp plain flour, for dusting

Batter

• 1 cup plain flour
• 2 tbsp cornflour
• 1 egg yolk
• 1 cup ice-cold sparkling water
• Ice cubes to keep the bowl cold

Dipping sauce

• ½ cup dashi (or water)
• 2 tbsp soy sauce
• 2 tbsp mirin
• Grated daikon and ginger

Method

1. Make the dipping sauce first: warm the dashi, soy and mirin together, then leave it to cool. Grate the daikon just before serving.
2. Separate the bouquets into small clusters with the stems still attached — three or four caps each. Do not cut the stems short; the length is the shape.
3. Heat the oil to 340°F. Lower than most frying, because tempura batter browns fast and you want it pale gold, not brown.
4. Dust the mushrooms lightly with plain flour. This is the step people skip, and it is why batter slides off.
5. Mix the batter at the last moment: whisk the yolk into the ice water, then tip in the flours and stir four or five strokes only. Lumps are correct. A smooth batter means developed gluten and a chewy shell. Sit the bowl in ice.
6. Fry in small batches — dip, let the excess run off, and lower into the oil. 90 seconds to 2 minutes, turning once. They should stay pale gold.
7. Drain on a rack and eat within three minutes. Tempura has a short and non-negotiable life.

Cold, lumpy, immediate

Three rules. Cold stops the gluten developing. Lumpy means you have not overworked it. Immediate because the batter starts to slacken within minutes of mixing. Professional kitchens mix tempura batter in small amounts continuously through service rather than making one bowl.

Sparkling water rather than still. The carbonation gives you a lighter shell, and the difference is genuinely noticeable side by side.

Other species that work

Maitake is the classic tempura mushroom in Japan — pull the rosette into large fronds and fry them flat. Beech mushrooms work in whole bouquets. Lion’s mane is too wet unless you press it first; see the species page.

Serving

The dipping sauce with grated daikon is traditional and correct. Otherwise: flaky salt and lemon, or a bowl of hot udon with the tempura balanced on the edge so it stays crisp.

Common questions