preheat oven to 450 degrees. rinse the fish and pat dry.
coat the fish with the flour and salt and pepper to taste. place fish in a roasting pan or baking dish. stuff the cavity with the fresh tarragon and about 2 tablespoons of the butter.
place the fish in the oven for 10 minutes. take the fish out and place the rest of the butter over the top. put the fish back in the oven for another 10 to 15 minutes. the top should start to look really crisp and brown. take the fish out of the oven and pour the whole bottle of wine over it and place in the oven for another 10 minutes.
remove from oven and place fish on a serving platter with lemon slices. pour sauce in pan over fish and serve.