Preheat your oven to 350°F (175°C). Prepare a 9x13 inch baking dish by greasing it or lining it with parchment paper.

In a large bowl, combine softened unsalted butter, brown sugar, and baking soda until smooth. Gradually add the rolled oats and flour until well incorporated.

Set aside 2 cups of the oat mixture for topping, then press the remaining mixture firmly into the bottom of the prepared baking dish.

Spread the apricot preserves evenly over the pressed crumble base.

Sprinkle the reserved oat mixture over the apricot preserves evenly.

Bake for 30 to 35 minutes until golden brown. The top should be bubbly around the edges.

Allow the dish to cool completely before slicing to ensure neat squares.