Ingredients

• 4 (6- to 7-oz) flounder or sole fillets
• All-purpose flour for dredging fish
• 2 to 3 tablespoons vegetable oil
• 1/4 cup finely chopped shallot
• 2/3 cup sweet vermouth
• 7 oz stemmed Champagne grapes (1 1/2 cups)
• 3 tablespoons unsalted butter, cut into tablespoon pieces
• 1 tablespoon fresh lemon juice

Instructions

1. Put oven rack in middle position and preheat oven to 250°F.
2. Rinse fish and pat dry. Season both sides of fillets with salt and pepper, then dredge in flour, shaking off excess.
3. Heat 2 tablespoons oil in a 12-inch heavy skillet over moderately high heat until it begins to smoke, then sauté 2 fillets, turning over once, until golden and just cooked through, about 4 minutes total. Transfer with a slotted spatula to a platter and keep warm, uncovered, in oven. Add more oil if necessary, and sauté remaining 2 fillets in same manner, transferring to platter.
4. Add shallot to skillet and cook over moderate heat, stirring, until softened, about 2 minutes. Add vermouth and simmer, scraping up any brown bits, 1 minute. Add grapes and cook over low heat, swirling skillet, until just heated through, 1 to 2 minutes.
5. Remove skillet from heat and add butter, swirling until incorporated. Add lemon juice and season sauce with salt and pepper. Spoon sauce with grapes over fish and serve immediately.