Preheat oven to 425°F

Wrap each filet with a slice of prosciutto

Heat a large ovenproof skillet over medium high heat until very hot. Add oil to pan, swirl to coat. Add fish, top side down.

Cook 2-3 minutes until prosciutto is lightly browned. Turn and repeat.

Transfer skillet to oven and bake at 425°F for 5 mins

Melt butter in a small skillet over medium heat. Cook for 2 mins until butter begins to brown. Add sage and remove pan from heat. Stir in sherry, and 1/8 tsp each salt and pepper.

Arrange fish on plates, spoon sage and butter sauce over fish, and serve immediately