Heat the dashi with the lemongrass and ginger on the gas burner until it's near to boiling.
Once it's hot invite your guests to sit down.
Add the vongole, shallots and mushrooms and cook for about 3 minutes to allow the flavour to develop.
Add a handful of green veggies and some fish. Allow to cook for a minute or two then spoon the hotpot out into bowls. Continue to cook until your guests are sated.
Note: lay a solid stone tile or board under the gas burner to protect the table.