In a large bowl combine 2 cups of flour, 2 cups quick cooking oats, 1 1/2 cups packed brown sugar, and 1 teaspoon of baking soda
Melt 1 1/4 cup of butter in a small saucepan
Pour melted butter on top of dry ingredients
Chop 2 cups of apples
Press half of butter and dry ingredients mixture into a greased 15x10x1 inch pan. Set aside the rest and bake for 8 minutes
In a small pan over medium heat combine 1 1/2 cup of caramel topping and 1/2 cup of flour. Bring to the boil stirring constantly. Boil for 2-3 minutes or until slightly thickened
Spread 2 cups of chopped apples and 1/2 cup of chopped walnuts onto baked crust. Then pour hot caramel mixture evenly over apples and nuts.
Sprinkle left over crumbly mixture over the top. Bake for 20-25 minutes and then left cool completely before cutting into