In large bowl, using electric mixer, combine cake mix (I use Duncan Hines), oats, and 6 tablespoons softened butter until crumbly. Scoop out 1 cup of these crumbs and set aside for topping.

To remaining crumbs, blend in egg. Press this mixture evenly into prepared pan. Bake for 12 minutes.

Turn reserved crumbs into bowl and add remaining 2 tablespoons butter, walnuts, sugar and cinnamon; beat at low speed until well mixed.

Spread pie filling on top of baked base. Sprinkle with cinnamon-crumb mixture. Return to oven and bake about 20 to 25 minutes longer or until crumbs are a light golden brown. Cool completely. Cut into wedges or squares. Top with whipped cream or ice cream. Makes 12 to 15 servings.