PREHEAT oven to 375° F. Grease or paper-line 18 muffin cups.
COMBINE flour, dry milk, 1 cup brown sugar, 2 teaspoons pumpkin pie spice and baking powder in large bowl. Mix pumpkin, butter, eggs and water in small bowl. Add to flour mixture; stir just until moistened. Spoon into prepared muffin cups, filling 2/3 full.
COMBINE remaining 1/2 cup brown sugar and 1/2 teaspoon pumpkin pie spice in small bowl. Sprinkle 1 heaping teaspoon over each muffin.
BAKE for 18 to 20 minutes or until wooden pick inserted in center comes out clean. Cool in pans on wire racks for 5 minutes; remove to wire racks to cool. Serve warm. Store any remaining tightly covered.