Peel and finely dice the onion and the garlic clove. Pick and roughly chop the parsley. Peel and finely dice the potatoes.
Heat a saucepan over a medium heat and add the butter. Sweat the onions until soft with a pinch of salt. Add the garlic, cook for a minute and then add the diced potatoes. Cook for a minute and then add the fish stock. Bring to the boil, reduce to a simmer and then cook until the potatoes are tender.
Whilst the potatoes are cooking prepare and cook the seafood.
Wash the mussels in cold water. Remove the beards and discard any mussels that are broken or cracked. If the mussels are open, gently tap them against your chopping board. If they close they are still alive and are good to cook. Any that remain open should be discarded.
Pick through the crab meat to remove any shell or cartilage.
To cook the mussels: heat a saucepan until hot. Add the mussels and the white wine to the pan cover with a lid and cook for 3 minutes or until all of the mussels are fully open. Pick the mussels from their shells. Strain the liquid through a fine sieve and keep to one side.
Once the potatoes are fully cooked, puree the soup base in a food processor until smooth. Add a splash more stock if the soup is too thick. Return the pureed soup to the pan, add the sweetcorn, crab and the mussels and heat thoroughly. Add the mussel cooking liquid, bring back to the boil and then check the seasoning.
Finish the chowder with a squeeze of lemon juice and the chopped parsley. Serve in small shot glasses or cups.
«If using fresh sweet corn make sure you cook the sweet corn in boiling water for 5 minutes before removing the kernels and using in the soup.»