In foodie folklore, the reason for this classic combination of fish and herb is that the oxalic acid in sorrel will dissolve the tiny bones that make Alosa sapidissima a trial to eat Not so. Tom Jaine, the British food historian, disproved this myth experimentally. He did not, however, go on to claim that the delicious recipe should be abandoned.*
Juice of ½lemon
1½poundsboned shad fillets
1 medium onion, peeled and thinly sliced
1bay leaf, crumbled
Wash the sorrel in two changes of water. Drain in a colander.
Put a third of the sorrel in a heavy medium saucepan with ½cup of water. Set over very low heat and let soften. Stir from time to time with awooden spoon. When the sorrel has wilted and condensed, add half of the remaining raw sorrel and another cup of water. Proceed as before. Add the rest of the raw sorrel to the saucepan with a final cup of water. When all the sorrel has softened, cover the pan, bring to a boil, lower the heat, and simmer very slowly for 5 minutes.
Drain the sorrel on a tamis or other strainer for 20 minutes. Discard the water that drains out. Then push the sorrel through the strainer with awooden spoon .
While the sorrel drains, make a blond roux with the butter and flour in a nonaluminum pan. Stir in the sorrel puree a little at a time. Cook slowly, over low heat, until the mixture thickens.
Meanwhile, sprinkle a shallow baking pan about as long as the shad fillets with salt, pepper, the oil, and the lemon juice. Whisk together and arrange the shad fillets in the marinade. Turn the fillets so as to make sure they are coated all over. Then arrange the onion slices over them and sprinkle with the parsley, thyme, and bay leaf. Let stand for 20 minutes.
When the sorrel is finished, remove from the oven and keep warm in a double boiler or bain-marie. Preheat the grill.
Drain the fillets. Place in an oval gratin dish or other pan large enough to hold the fillets in a single layer. Set on the second highest level of the oven.
Grill for 5 minutes. Turn the fillets. Brush with oil and continue cooking for another 10 minutes at the next lowest level of the oven or until the flesh is just cooked through.
Spread the sorrel puree on a long serving platter. Then lay the fillets over the sorrel and serve.
*Shad are more famous for their abundant roe than for their flesh. H. L. Mencken once praised American women for being “fecund as the shad.”