HEAT oven to 350ºF.
BEAT 1/2 cup butter, cake mix, eggs and applesauce with mixer 2 min. or until well blended. Stir in 1/2 cup chopped ginger. Pour into 13x9-inch baking dish sprayed with cooking spray.
BAKE 45 to 50 min. or until toothpick inserted in center comes out clean. Cool completely.
BEAT cream cheese and remaining butter in large bowl with mixer until well blended. Add vanilla and ground ginger; mix well. Gradually beat in powdered sugar. Spread onto cake. Garnish with remaining chopped ginger. Keep refrigerated.