Preheat oven to 400 degrees F. Place 2 tablespoons of the butter in a 10-inch ovenproof skillet. Place in oven for 3 to 5 minutes or until butter melts. Meanwhile, for batter, in a medium bowl use a wire whisk or rotary beater to beat eggs until combined. Add flour, milk, and salt; beat until mixture is smooth. Immediately pour batter into the hot skillet. Bake for 20 to 25 minutes or until edges are puffed and pancake is well browned.
Meanwhile, in a medium saucepan melt remaining 2 tablespoons butter over medium-low heat. Stir in brown sugar and lemon peel, stirring until sugar dissolves. Stir in grapes, nectarine and mint; heat through. Fill pancake with fruit mixture. Cut into wedges and serve warm. If desired, top with powdered sugar. Makes 6 servings.