Preheat your oven to 190°c (170°c for fan-assisted ovens, Gas Mark 5 or 375°F) and grease & line a 900g (2lb) loaf tin with grease-proof paper. Set aside.
In a large bowl, mash the bananas with a fork. Add the sugar, butter/margarine, egg & vanilla extract and mix until combined.
Gradually add the flour and baking powder, mixing until all combined.
Pour half the batter into your pre-lined loaf tin and smooth into the corners.
Warm your Biscoff spread in the microwave for about 10-20 seconds to soften it slightly. Drizzle a couple of spoonfuls over the batter in the loaf tin before adding the remaining batter on top.
Drizzle the remaining Biscoff spread over the top of your loaf, before stirring the batter with a skewer to create the marbled affect. Crumble a few broken Biscoff biscuits on top.
Bake in your preheated oven for about 40 minutes until golden on top. Leave to cool in the loaf tin and serve in slices.
Notes
If you think your Biscoff Banana Loaf is looking a little brown on top towards the end of its baking time, simply pop a little tin foil over the top of your tin. This will stop it from baking more on top while letting it continue to bake inside.