How to Make It
In a saucepan of boiling water, blanch the tomatoes until the skins just wrinkle, 30 seconds. Drain and cool under running water, then peel and cut into 1/4-inch dice.
Wipe out the saucepan and melt the butter in it. Add the shallots and cook over moderate heat, stirring, until softened, about 2 minutes. Add the wine and simmer over moderately high heat until reduced by half, about 3 minutes. Add the fish stock and simmer until the liquid is reduced to 1/2 cup, about 3 minutes. Add the heavy cream and simmer until thickened, about 3 minutes. Stir in the diced tomatoes, herbs, vermouth and nutmeg. Season the sauce with salt and pepper.
Preheat the broiler and position the rack 8 inches from the heat. Season the sole lightly with salt and pepper and transfer to a 2-quart flameproof baking dish. Spoon the sauce on top and broil for 8 to 10 minutes, until the sauce is bubbling and the fish is just cooked through. Let stand for 5 minutes before serving with crusty bread.