Heat oven to 350 degrees. Grease 8-inch square pan. In large bowl, heat brown sugar and margarine until light and fluffy; beat in egg. Lightly spoon flour into measuring cup; level off. Add flour, baking soda, 1 teaspoon cinnamon, nutmeg and salt; mix well. Stir in apples. Spread batter in greased pan. Bake at 350 degrees for 25 to 35 minutes or until toothpick inserted in center comes out clean. Meanwhile, combine all sauce ingredients in small saucepan. Heat over medium heat until butter melts and sauce is hot, stirring frequently. Serve warm sauce over warm cake. 9 servings. High Altitude: above 3500 feet: Increase flour to 1-1/4 cups. Bake at 350 degrees for 30 to 40 minutes. 330 calories, 14 g fat, 45 mg cholesterol and 330 mg