Preheat oven to 350°. In a large bowl combine first 3 ingredients. Blend with mixer at low speed until crumbly(may use food processor). Stir in nuts. Press 2 3/4 cups crumb mixture into an ungreased 13X9-inch pan. To remaining mixture add cinnamon, soda, salt, sour cream, vanilla and egg. Blend well. Stir in apples. Spoon evenly over crumb layer. Bake 25 to 30 minutes or until toothpick inserted in center comes out clean. Cut into squares and serve with whipped cream. Can be served warm or cold. Serves 12 - 15.