Preheat the oven to 175°C or 155°C Fan
Grease and line a large loaf tin (the one I used measured 25 x 11.5 x 7.5cm)
Sift gluten-free flour, baking soda and salt into a medium bowl and whisk together
In the bowl of an electric mixer, beat the butter and 170g of the caster sugar on a medium speed for 5 minutes until pale and fluffy, scraping down the sides when necessary
Whilst the butter and sugar mixes, mash the bananas thoroughly in a small bowl
Crack the eggs into the butter and sugar mixture one by one, mixing the first through fully before adding the second
Add the mashed bananas and mix
Add half of the flour mixture and mix on a low speed until just incorporated, followed by half of the greek yoghurt/baking soda mixture. Repeat with the second half of the flour mixture, then the greek yoghurt mixture.
Add the chocolate chips and mix through on a low speed or by hand
Pour half of the mixture into the lined loaf tin
In another small bowl, whisk together the cream cheese, biscoff spread, cinnamon, the remaining 50g of caster sugar and vanilla extract.
Spoon half of the Biscoff mixture in a line down the middle of the tin, on top of the batter. Use a skewer or knife to lightly marble it through the batter, making figure of 8 motions. This shouldn't be too thorough - you don't want to mix them together completely, just spread the Biscoff out a little.
Pour the other half of the batter on top, followed by the other half of the Biscoff, repeating the same marbling technique.
Bake for approx 1 hour 15 - 1 hour 30 minutes or until a skewer comes out with just a few moist crumbs. If the top becomes too browned (keep an eye on it after the 45 minute mark), cover loosely with foil and continue cooking.
Leave to cool in the tin for 10 mins, before transferring to a cooling rack
After about an hour, once fully cooled, spread more of the homemade Biscoff across the top
Slice and enjoy!