Preheat the oven to 180°C.
Lightly grease a 2lb loaf tin (I used this one by Circulon) and line with greaseproof paper (see notes in the post above for how to do this). Set the baking tin aside.
In a large bowl, beat the margarine and golden caster sugar together until creamy.
Mix in the eggs one at a time, adding 2 tablespoons of the 280g flour after each egg to stop the mixture from curdling.
Fold in the remaining flour, salt and ground cinnamon until fully combined.
In a separate bowl, mash the bananas until smooth. Add to the cake mixture, along with two-thirds of the chocolate chunks and fold everything together.
Spoon half of the cake mixture into the loaf tin, smoothing it out the top.
Now melt the Biscoff spread in a bowl for 10-20 seconds in the microwave, and then pour on top of the layer of cake mixture in the baking tin.
Top with the remanining cake mixture and use a skewer or toothpick to gently swirl the layers together.
Scatter the remaining chocolate chunks on top.
Bake for 60-70 minutes* until risen, golden in colour and a toothpick inserted into the middle comes out crumb-free.
Leave the cake to cool in the baking tin for 15 minutes, then transfer to a wire rack and leave to cool completely.
To decorate, melt a tablespoon of Biscoff Spread and drizzle over the banana bread. Finish by placing a few Biscoff Biscuits on top.