Preheat oven to 500°.

Cut the fillets into twelve strips weighing 4 oz each. (Equal size portions ensure equal amount of doneness when cooked.) Season with salt and pepper.

Thoroughly wash sorrel and remove stems. Slice into julienne and reserve.

Butter a large oven-proof saucepan and sprinkle with the minced shallots. Arrange the fillets atop the shallots.

Pour in the vermouth and fish stock and add half the sorrel. Cover with buttered foil, buttered side down, touching the fish.

Over high heat, bring the liquid to a boil. Transfer the pan to the oven and bake the fish approximately 5 minutes, or until the fish feels springy to the touch. Transfer fish to a warm plate and cover with the foil. Reserve the cooking liquid.

In a separate pan, heat 1/2 tbsp butter. Sauté the remaining half of the sorrel until wilted. Strain the reserved cooking liquid over the sorrel, add the cream, and reduce until thickened. Whisk in the remaining 7-1/2 tablespoons butter, one piece at a time. Season with salt and pepper to taste.