Preheat oven to 325°. Spray an 11″x 7″ baking pan with cooking spray.
Whisk together flour, oats, brown sugar, salt, baking soda, and cinnamon in a medium bowl. Drizzle butter and orange juice over flour mixture. Stir until moistened and mixture is crumbly.
Reserve 1/2 cup of crust mixture. Press remaining crust mixture into bottom of prepared pan.
In a medium bowl, combine all ingredients and stir well. Spread filling mixture over crust in pan. Sprinkle evenly with reserved crust mixture.
Bake for 40-45 minutes, or until edges are golden. Cool completely in pan on wire rack.
Makes 24 bars.