Citrus soy sauce (Ponzu)

1. Squeeze the lemon, lime and yuzu – about 100 ml juice in total – and strain out the seeds.

2. Boil the mirin in a small pan for 1 minute to cook off the alcohol, then let it cool.

3. Pour the soy sauce, citrus juice, rice vinegar and cooled mirin into a clean jar.

4. Add the kombu and katsuobushi, seal and leave to mature in the fridge for at least one night (ideally 1-2 days).

5. Strain through a fine sieve, pressing the katsuobushi in the sieve with a spoon.

6. It keeps for 1 month in the fridge; serve it with hot pots, gyōza, tataki and salads.

Tip: Ponzu is the all-purpose light dipping sauce of Japanese cooking – the citrus aroma lifts the flavour of fish and grilled meat. A mix of lemon and lime works instead of yuzu, as here.