Yield: 12 to 16 squares

2 cups all-purpose flour
2 cups firmly packed brown sugar
1/2 cup butter, softened
1 cup walnuts, chopped
1 to 2 teaspoons ground cinnamon
1 teaspoon baking soda
1/2 teaspoon salt
1 cup sour cream
1 teaspoon vanilla extract
1 egg
2 cups Granny Smith apples, peeled and finely chopped

Preheat oven to 350 degrees F.

In a large bowl combine flour, brown sugar and butter. Beat at low speed until crumbly. Stir in nuts. Press 2 3/4 cups of crumb mixture into bottom of ungreased 9 x 13 x 2-inch baking pan.

To remaining mixture add cinnamon, baking soda, salt, sour cream, vanilla extract and egg. Mix well. Stir in apples. Spoon evenly over base. Bake for 25 to 35 minutes or until wooden pick inserted in center comes out clean. Cut into squares, spread caramel frosting atop squares while hot, and serve warm with whipped cream or ice cream.

Caramel Frosting
1/3 cup butter
1/2 cup firmly packed dark brown sugar
3 tablespoons milk
1/2 teaspoon vanilla extract
1 1/2 cups confectioners' sugar

Melt butter; add sugar and a dash of salt. Stir until combined, add milk, and bring to a boil. Remove to a small mixing bowl and let cool for 10 minutes.

Add vanilla extract and confectioners' sugar until spreading consistency. Spread on hot squares.