1Heat oven to 350°F (if using dark or nonstick pan, heat oven to 325°F). In large bowl, mix flour, oats, brown sugar, hazelnuts and baking soda, using pastry blender (or pulling 2 table knives through ingredients in opposite directions). Stir in butter until well mixed.
2In small bowl, reserve 2 cups oat mixture for topping. On bottom of ungreased 15x10x1-inch pan, firmly press remaining oat mixture. Bake 15 to 18 minutes or until crust just begins to brown.
3Carefully spread pie filling over warm crust. Stir cinnamon into reserved oat mixture. Sprinkle oat mixture over filling; press lightly into filling.
4Bake 20 to 25 minutes or until top is deep golden brown. Cool completely in pan on wire rack, about 30 minutes. For bars, cut into 8 rows by 6 rows.