Preheat your oven to 350 degrees Fahrenheit. Lightly grease a 9×9 inch baking pan or line it with parchment paper, leaving an overhang on two sides to make it easy to lift the bars out once they are cooled.
In a large mixing bowl, combine the all-purpose flour, rolled oats, brown sugar, salt, and cinnamon. Use a pastry cutter or your clean fingertips to work the cold, cubed butter into the dry ingredients. Continue until the mixture looks like coarse crumbs and no large chunks of butter remain.
Take approximately two-thirds of the crumble mixture and press it firmly into the bottom of your prepared baking pan. Make sure it is an even layer and pushed into the corners to create a solid base for the fruit. Set the remaining crumble mixture aside for the topping.
In a medium bowl, toss together the cranberries, granulated sugar, cornstarch, orange zest, orange juice, and alcohol-free vanilla extract. Stir well until the cranberries are evenly coated with the sugar and starch mixture.
Pour the cranberry mixture over the pressed crust and spread it out into an even layer. Take the remaining crumble mixture and sprinkle it evenly over the top of the cranberries, leaving some small clusters for a nice texture.
Place the pan in the oven and bake for 40 to 45 minutes. The edges should be golden brown and the cranberry filling should be bubbling through the crumble topping. Remove from the oven and allow the bars to cool completely in the pan before slicing into squares.
