Ingredients:

Topping
1cup Gold Medal™ all-purpose flour
1/2 cup packed brown sugar
1/4 teaspoon salt
1/2 cup butter, cut into small pieces
Apple Mixture

6 apples, peeled, thinly sliced
3 tablespoons packed brown sugar
1 teaspoon ground cinnamon
2 teaspoons lemon juice
Cake

1 box Betty Crocker™ SuperMoist™ yellow cake mix
1 1/3cups water
1/3 cup oil
3 eggs

Directions:

1 Heat oven to 350°F (325°F for dark or nonstick pan). Spray bottom and sides of 13×9-inch pan with baking spray with flour.
2 In medium bowl, stir together flour, 1/2 cup brown sugar and the salt. With pastry blender or fork, cut in butter until mixture is crumbly. Set aside.
3 In another medium bowl, gently stir together Apple Mixture ingredients; set aside.
4 In large bowl, beat Cake ingredients with electric mixer on low speed 30 seconds, then on medium speed 2 minutes, scraping bowl occasionally. Pour into pan.
5 Spread apple mixture evenly over cake batter. Sprinkle Topping evenly over top.
6 Bake 30 to 35 minutes or until toothpick inserted in center comes out clean. Cool completely, about 30 minutes.

source:tomatohero.com