1Heat oven to 350°F. Lightly spray 9-inch square pan with cooking spray.
2In large bowl, stir together gingerbread mix, water, egg and diced apples. Spoon into pan.
3In small bowl, mix butter, brown sugar, flour, cinnamon and salt with fork until crumbly. Sprinkle evenly over gingerbread batter.
4Bake 35 to 40 minutes or until toothpick inserted in center comes out clean. Serve warm or cold.