Preheat the oven to 200°C / Gas Mark 6.
Unroll the puff pastry onto a floured surface, use an upside down 20-23cm ovenproof frying pan as a template to cut out a disc of pastry and leave in the fridge until you are ready to use it.
Melt the butter in the frying pan, stir in the Whitworths Light Soft Brown Sugar and cook over a medium heat for about 4-5 minutes until the butter and sugar turn into a golden caramel. Take the caramel off the heat and leave to get cool, but not firm.
Cut the bananas into 1/3’s lengthways. Arrange in the caramel, lay the pastry disc on top of the bananas and tuck the edges down the sides of the pan. Bake for 20-25 minutes in the oven until the pastry is golden brown. Leave to cool for about 5 minutes before turning out.
To turn the tart out, put an upturned, large plate on top of the pastry. Spread your hand across the plate to get a good grip. Quickly flip the pan upside down and then carefully lift it off.