Preheat your oven to 350°F (175°C). Line your 8x8-inch baking pan with parchment paper, leaving some overhang on the sides for easy removal of the bars once baked.
In a large bowl, combine the all-purpose flour, rolled oats, brown sugar, salt, and cinnamon. Using a pastry cutter or fork, cut the cold, cubed butter into the dry ingredients until the mixture resembles coarse crumbs with some pea-sized pieces. Reserve about 1 cup of this mixture for the topping.
Press the remaining crumble mixture firmly and evenly into the bottom of the prepared pan. This will form the sturdy base of your bars. Bake the crust for 12-15 minutes, or until it’s lightly golden. Remove it from the oven and set aside.
While the crust is baking, combine the cranberries, orange juice, honey or maple syrup, and orange zest in a small saucepan. Cook over medium heat, stirring occasionally, until the cranberries burst and the mixture thickens slightly, about 8-10 minutes. Remove from heat and let cool for a few minutes.
Pour the cranberry orange filling evenly over the pre-baked crust. Sprinkle the reserved crumble topping evenly over the filling, then finish by scattering the sliced almonds on top.
Return the pan to the oven and bake for another 20-25 minutes, or until the topping is golden brown and the filling is bubbling around the edges. Allow the bars to cool completely in the pan before lifting them out and slicing into squares.
