Do not throw away the butter sauce if you have any left. It will keep for about a week in the refrigerator. Brush on large shrimp or scallops before grilling in a skillet or on the grill. Delicious! Sorrel is a broad leaf herb with a lightly acidic taste. While waiting to grow it in your garden this summer, you can easily find it in the fruit and vegetable aisle in some supermarkets. The Marvini brand offers sorrel among a large variaty of bagged ready-to-use fresh herbs.