1. Preheat the oven to 180C/350F/gas mark 4. In a small bowl, combine the bananas, vanilla and melted butter, stirring gently until the banana slices are well coated.
2. Unroll the croissant dough and separate into squares (the dough will be perforated into triangles, and two triangles make a square shape). Place each square of dough on a lightly greased baking tray and spoon some of the bananas into the centre of each. Bake for 10 minutes, or until the pastry is golden brown.
3. Heat the caramel topping and drizzle over the banana squares. Serve warm.