HEAT oven to 400°F.
COMBINE first 4 ingredients; set aside. Mix egg, oil, applesauce, brown sugar and 1/2 tsp. vanilla in large bowl. Add dry ingredients; stir just until moistened. Stir in carrots.
SPOON into 12 muffin cups sprayed with cooking spray. Bake 15 min. or until toothpick inserted in centers comes out clean. Cool in pan 5 min. Remove to wire racks; cool.
MIX reduced-fat cream cheese, powdered sugar and remaining vanilla until well blended; spread onto muffins.