1 cup butter
1/4 cup Japanese sherry
1/2 cup olive oil
1 head fresh prawns
Place butter in a large saucepan of salted boiling water. Boil 1 minute, until butter is heated through. Set aside.
In a small bowl, whisk together sherry vinegar and 1 1/2 teaspoons rice vinegar. Pour over prawns in saucepan.
Place prawns in saucepan with 1/2 cup of chicken stock. Cover, and cook over low heat about 10 minutes, turning prawns once, until golden brown.