1kglarge cockles, cleaned and any open cockles discarded
For the Tosazu beurre blanc
60mlTosazu, rice vinegar seasoned with katsuobushi
250gcold unsalted butter, cubed
1teaspoonwhite wine vinegar
fine salt
black pepper
Instructions
Tosazu beurre blanc
In a saucepan over low heat, bring the Tosazu to a simmer. Remove from the heat and gradually add the butter, whisking continuously, as though making a mayonnaise.
Stir in the white wine vinegar and adjust the seasoning with fine salt.
Keep warm, at 60°C (140°F), until ready to serve.
Just before serving
Put a large pan over high heat.
Once very hot, tip the cockles into the pan and add a glass of water to create steam. Cover the pan immediately. After 1 minute, the shells will be just open. Drain the cockles, reserving the cooking liquid. Discard any cockles that have not opened.
Presentation
Divide the cockles between soup plates. Stir 1 tablespoon of the cockle cooking liquid into the beurre blanc and pour over the cockles. Finish with some freshly ground pepper.