Preheat the Oven: Begin by heating your oven to 350°F (175°C). Prepare a 9x13-inch baking dish by greasing it or lining it with parchment paper for effortless cleanup.

Prepare the Crust and Crumble: In a spacious bowl, mix together the cake mix, rolled oats, and melted butter until well blended. Mix until the ingredients are evenly combined and crumbly in texture.

Assemble the Bars: Pat roughly two-thirds of the crumble mixture evenly into the bottom of the prepared pan to form a solid base. Evenly distribute the cherry pie filling on top of the crust.

Top with Crumble: Sprinkle the remaining crumble mixture evenly over the cherry filling.

Bake: Place in the preheated oven and bake for 30 to 35 minutes, or until the top turns a golden brown and the filling begins to bubble.

Cooling and Serving: Once baked, take the bars out of the oven and allow them to cool in the pan. Once fully cooled, cut into squares or rectangles and enjoy!