Preheat the oven to 180°C.
To a mixing bowl, add the reduced-fat spread, sweetener, flour, egg, and vanilla mix with an electric whisk until the mixture is thick and creamy. Place the Biscoff spread into a small microwaveable bowl and microwave in small bursts until melted. Add the Biscoff spread into the cake mixture and whisk again until combined.
Pour the mixture into 4 holes of a silicone muffin tray and flatten out. Bake for 12-14 minutes, until an inserted skewer comes out clean. Leave to cool completely.
Once the cakes are cooled, make the creamy layer. Place the low-fat double cream alternative in a medium mixing bowl. Whisk with an electric hand whisk, on high speed for about 2-4 minutes, until soft peaks are formed. Take care not to over-whisk the cream alternative – otherwise it will become too stiff to fold in the remaining ingredients.
Place the Biscoff spread into a small microwaveable bowl and microwave in small bursts, until melted and completely smooth.
Add the yoghurt, melted Biscoff spread and vanilla essence to the bowl with the whipped cream alternative. Fold in gently using a rubber spatula or large metal spoon until completely combined. Take care not to knock the air out of the mixture.
Once the sponges have cooled, remove from the silicone tray and cut each cake in half horizontally to create 2 circle pieces. You should have 8 slices of sponge. Put to one side.
Now you are ready to assemble. Add a little of the cream mixture to the bottom of the serving dishes. Add a slice of sponge, a few of the banana slices, sprinkle over some of the crumbled biscuit. Repeat the layers again finishing with a layer of cream mixture on-top. Leave in the fridge for 30 minutes or until ready to serve.
When ready to serve, add a swirl of aerosol cream and sprinkle over the remaining biscuit crumbs. Serve.