Preheat oven to 325 degrees Fahrenheit (165 degrees Celsius).

In the bowl of a mixer, combine flour, oats, brown sugar, salt, baking soda, and cinnamon.

Add the oil and juice and mix until moistened (mixture will be crumbly).

Reserve a full half cup of this mixture for the topping. Press the remaining mixture on the bottom of a nine- by 13-inch (20- by 30-centimeter) baking pan lined with Gefen Parchment Paper.

Combine all ingredients in the bowl of a mixer on low speed and mix until well combined. Spread carefully over the crust.

Sprinkle reserved oat mixture evenly over the filling. Bake for 40 minutes or until edges are golden.

Cool completely in the pan on a wire rack. These squares freeze well.