Preheat your oven to 350 degrees F (175 degrees C). This temperature is crucial for achieving the right texture in your bars. While the oven is heating, prepare an 8x8 inch pan by lining it with parchment paper and generously spraying it with nonstick cooking spray. This prevents sticking and makes cleanup a breeze.
In a large mixing bowl, combine the oat flour, old-fashioned rolled oats, brown sugar, ground cinnamon, and salt. Use a fork to mix these ingredients until they are well blended. You want to ensure that the sweetness of the sugar and the warmth of the cinnamon are evenly distributed throughout the dry ingredients.
Next, add in the melted butter, vanilla extract, and almond extract. Stir this mixture until a nice crumble forms, and the dough begins to clump together. You’re aiming for a texture that is somewhat crumbly but holds together well when pressed.
Set aside 1 ½ cups of this mixture to form the base of your bars. Press this mixture evenly into the bottom of your prepared pan using your hands. This step is important as it creates a solid foundation for your cherry filling.
Now for the cherry filling! Place a medium pot over medium heat and add in your frozen tart cherries, pure maple syrup, almond extract, cornstarch, and a pinch of kosher salt. Use a wooden spoon to gently press down and break down the cherries just a bit. This helps release their juices and flavors.
Bring the mixture to a gentle boil. Once boiling, reduce the heat and continue cooking for about 5 minutes. You want the filling to thicken nicely, coating the back of your spoon without being too drippy. If it appears too runny, stir in 1-2 teaspoons more of the cornstarch or arrowroot.
Pour this luscious cherry mixture over the pressed base in your pan. Use a spoon to spread it evenly, ensuring every part of the crust gets a taste of that sweet filling.
Retrieve the remaining crumble mixture from the fridge. By now, it should have clumped together nicely. Sprinkle this topping generously over the cherry filling, ensuring it's evenly distributed for that perfect texture.
Place your pan in the preheated oven and bake for about 30 minutes, or until the filling is bubbly and the topping is golden brown. This is where the aroma of baking fills your kitchen and gets everyone excited!
Once done, allow the bars to cool completely on a wire rack. After cooling, transfer them to the fridge to chill. They can be served at room temperature or chilled; both options are absolutely delicious. When ready to serve, use a sharp knife to cut them into 16 squares, and watch everyone enjoy your creation!
