Preheat oven to 350 F, and grease an 8x8 or 9x9 baking dish with foil and then spray with non-stick cooking spray.
Using a fork & knife or a pastry blender, combine the softened butter, brown sugar, baking soda, oats and flour until crumbly.
Measure out 2 cups of the crumble mixture and gently press into the bottom of the baking dish.
Carefully spread the blueberry pie filling over the crust stopping about 1/4" from the crust edge.
Sprinkle the remaining crumble topping over the top of the pie filling.
Bake in the preheated oven for 30 to 35 minutes.
Let cool for at least 10 minutes on a cooling rack, and cut into bars.
Serve Blueberry Crumble Bars for breakfast, snack or dessert.