Blend:

2 cups flour
2 cups packed brown sugar
1/2 cup softened butter

until it forms crumbs. Stir in 2 cups chopped nuts and press into bottom of a 9x13 or 15x10 pan.
Combine remaining crumb mix with

1 or 2 tsp cinnamon
1 tsp soda
1 cup sour cream
1 tsp vanilla
1 egg
Blend well and stir 2 cups peeled and chopped apples into batter.

Bake at 350 degrees for 30 to 40 minutes. Drizzle with white icing or powdered sugar.