In a large mixing bowl, whisk together flour, crushed Biscoff cookies, brown sugar, cinnamon, and salt. Add cold butter and mix until crumbly.

Preheat your oven to 325°F and grease a loaf pan.

In a stand mixer, beat butter until creamy, then add sugar and mix until fluffy. Add eggs, vanilla, and mashed bananas until just combined.

In a separate bowl, whisk flour, baking soda, and salt. Fold into wet mixture until combined.

Pour half of the batter into the prepared loaf pan, drizzle with melted cookie butter and add the rest of the batter on top.

Sprinkle the crumb topping evenly over the batter.

Bake for 60-65 minutes or until a toothpick comes out with moist crumbs.

Let the bread cool in the pan for 15-20 minutes before transferring to a wire rack.