Poached Fish with Ginger and Lemon Thyme

This recipe varies little from one that appeared in Martha Washington’s Booke of Cookery, annotated by the culinary historian Karen Hess. You can use any fish you like; just don’t overcook it or let the liquid boil. I like to use sea trout (the southern form of weakfish), as we did here; the skin is thin and delicious. Buy whole fish, have the fishmonger fillet them for you, then bring the head and backbone home to make a stock to flavor the dish. Simply place the head and bones (wit