In a saucepan, combine the apples, water, brown sugar, lemon juice and cinnamon. Bring to a boil. Reduce heat; cover and simmer for 8-10 minutes or until apples are tender. Remove from the heat and set aside., In a bowl, beat the egg, sugar, buttermilk, molasses and oil. Combine the flour, baking powder, baking soda, ginger, salt and nutmeg; stir into buttermilk mixture just until combined. Combine cornstarch and cold water until smooth; stir into apple mixture. Pour apple mixture into 8-in. square baking dish coated with cooking spray. Spread gingerbread mixture over apples. Bake at 350° for 25-30 minutes or until a toothpick inserted into the topping comes out clean.