Prepare a grill 5 to 6 inches from heat. Place peach havles in a heat-proof bowl and coat with butter. Grill the peaches, cut side down until softened and lightly marked. Turn once to often slightly from the back. This will take 5 or 6 minutes. In the same bowl, combine brown sugar, lemon juice, cinnamon, vanilla extract, salt and nutmeg. Add the peaches from the grill and gently toss. Cover with plastic wrap and let stand for about 20 minutes. Serve warm with vanilla ice cream. A variation includes using sliced pineapple instead of peaches. Serves 6 to 8.