Preheat Oven: Preheat your oven to 350°F (175°C). Spray an 8×8 or 9×9-inch baking dish with non-stick cooking spray.
Make the Crumble Mixture: In a mixing bowl, combine the softened butter, brown sugar, baking soda, rolled oats, and flour. Use a fork and knife or a pastry cutter to mix the ingredients until they form a crumbly texture.
Form the Crust: Measure out 2 cups of the oat mixture and gently press it into the bottom of the prepared baking dish to form an even crust.
Add the Apricot Layer: Carefully spread the apricot preserves over the crust, leaving about 1/4 inch of space from the edge of the crust.
Top with Crumble: Sprinkle the remaining oat mixture over the top of the apricot preserves to form the crumble topping.
Bake: Place the baking dish in the preheated oven and bake for 30-35 minutes, or until the top is golden brown and the preserves are bubbly.
Cool and Serve: Allow the bars to cool completely in the baking dish before cutting them into squares. Serve and enjoy!