Preparation Pat scallops dry and sprinkle with 1/4 teaspoon each of salt and pepper (total). Heat 1 tablespoon butter in a 12-inch nonstick skillet over medium-high heat until foam subsides, then sear scallops, turning once, until golden brown and just cooked through, about 5 minutes total. Transfer to a platter. Add shallot, wine, and vinegar to skillet and boil, scraping up brown bits, until reduced to 2 tablespoons. Add juices from platter and if necessary boil until liquid is reduced to about 1/4 cup. Reduce heat to low and add 3 tablespoons butter, stirring until almost melted, then add remaining 3 tablespoons butter and swirl until incorporated and sauce has a creamy consistency. Stir in tarragon and salt to taste; pour sauce over scallops.
Preparation Pat scallops dry and sprinkle with 1/4 teaspoon each of salt and pepper (total). Heat 1 tablespoon butter in a 12-inch nonstick skillet over medium-high heat until foam subsides, then sear scallops, turning once, until golden brown and just cooked through, about 5 minutes total. Transfer to a platter. Add shallot, wine, and vinegar to skillet and boil, scraping up brown bits, until reduced to 2 tablespoons. Add juices from platter and if necessary boil until liquid is reduced to about 1/4 cup. Reduce heat to low and add 3 tablespoons butter, stirring until almost melted, then add remaining 3 tablespoons butter and swirl until incorporated and sauce has a creamy consistency. Stir in tarragon and salt to taste; pour sauce over scallops.