Heat oven to 400. Spray bottoms only of 12 medium muffin cups, 2 1/2 x 1 1/4 inches, with nonstick cooking spray, or line with paper baking cups.
Mix oats and buttermilk in large bowl.
Beat in brown sugar, oil, molasses, vanilla and egg whites. Stir in remaining ingredients except peaches just until flour is moistened (batter will be lumpy). Fold in peaches.
Divide batter evenly among muffin cups (cups will be full). Sprinkle with sugar if desired.
Bake about 20 minutes or until golden brown. Remove from pan.