Preheat a combi oven on steam to 84°C (183°F).
Whisk the eggs in a bowl and add the dashi. Add the soy sauce and pass the egg mixture through a fine chinois. Measure 40 ml (1¼ fl oz) of the egg dashi mixture into eight ovenproof bowls (with a base area 6 cm/2½ in wide) and wrap each bowl tightly in plastic wrap. Place the bowls in the combi oven and steam for 7 minutes or until just set. Remove from the oven and leave to rest, still covered with the plastic wrap, for 10 minutes.