Preheat the oven to 325˚F. Lightly spray a 9x13 inch baking dish with cooking spray.
For the Crust: In a medium bowl, mix together the flours, sugar, oats, salt, baking soda and cinnamon. Pour in the butter and lemon juice, and mix until fully incorporated. (mixture should be crumbly)
Reserve ½ cup of the oat mixture. Press the crust mixture into the prepared baking dish.
For the Filling: In a medium bowl, mix together the filling ingredients until fully combined. Spread the mixture over the crust and sprinkle the reserved oat mixture evenly over the cranberry mixture.
Bake the 40 minutes, or until the edges are golden. Allow to cool before cutting into squares.