How to Make It
Preheat the oven to 450°. In a large, shallow dish, mix 2 tablespoons of the lime juice with the olive oil. Add the halibut fillets and turn to coat. Refrigerate for 15 minutes.
In a medium skillet, combine the fish stock, wine, shallot, white peppercorns, bay leaf and the remaining 2 tablespoons of lime juice. Boil over high heat until reduced to 1/2 cup, about 6 minutes. Add the cream, bring to a boil and simmer over moderately low heat until reduced to 2/3 cup, about 10 minutes. Strain the sauce into a small saucepan.
Season the halibut fillets with salt and white pepper and transfer them to a large rimmed baking sheet. Bake in the upper third of the oven until just cooked through, about 10 minutes.
Add the olives to the cream sauce and bring to a boil. Pour in any accumulated fish juices. Remove the sauce from the heat and whisk in the butter until incorporated. Stir in the parsley and season with salt and white pepper. Set the halibut fillets on warmed plates, spoon the sauce on top and serve.