Spread a stick of butter, softened, into an 8-inch or 9-inch pie plate. Sprinkle approximately 1/2 cup of brown sugar, 1/2 cup of raisins, and 1/2 cup of walnuts, and smash down.
Roll out half of the double pie crust and place on top of sugar, nuts and raisins mixture. Add the apple pie filling. Roll out the other half of the pie crust and place on top of pie filling, seal and flute edge.
Bake in a 350-degree oven. Place foil under the pie, as this most likely will spill over. Bake approximately for 1 hour or until crust is golden.
When done, place a large plate on top of pie and flip over. Let it sit for a minute so the gooey topping can release from the pan. Scrape out any remaining topping onto the pie.