Set aside. In large bowl, beat 1/2 cup brown sugar, the milk, oil, vanilla and egg until well blended. Stir in flour, baking powder and salt just until ingredients are moistened. Fold in peaches and 1/2 cup pecans. Divide batter evenly among muffin cups (cups will be almost full). Sprinkle with topping. Bake 18 to 20 minutes or until golden brown. Immediately remove from pan to cooling rack.