Turn on broiler. Melt butter in a heavy non-reactive saucepan over low heat. Sauté garlic 4-5 minutes or until softened. Remove from heat and stir in olives and scallion. Set aside 30 minutes to let flavors combine.

 

Season flank steak with salt and pepper to taste. Broil 5-6 minutes per side for medium done meat. Remove from broiler and let stand 5 minutes. Slice across grain into 1/4" slices.

 

Serve with olive sauce.