Wash the salmon steaks under cold running water. Pat dry. Season with salt and pepper.
Heat the oil and butter in a frying pan and cook the steaks over medium heat for 2 minutes on each side. Add the white wine and simmer for 10 minutes. Transfer the salmon steaks to a platter; cover with foil and reserve in a warm place.
Pour the cooking liquid in the frying pan into a medium saucepan. Add the heavy cream and boil for 5 minutes.
Combine the butter and flour in a small bowl. Mix well to form a paste. Drop pieces of the butter and flour mixture into the boiling liquid. Whisk until the sauce is smooth and medium thick. Season with salt and pepper to taste.
Simmer the sauce over low heat for about 10 minutes.
Bone and skin the salmon steaks. Arrange on warm plates. Divide the sauce between each plate pouring the sauce over the salmon steaks. Serve at once.