Roll out the puff pastry into a thin sheet and spread it with nutella.
Layer chopped nuts (hazelnuts, walnuts or any other, according to your taste. You can also use raisins, dried fruit or other ingredients that suit your roulade) on top of nutella.
Place the bananas on the edge, fold the sides so that nutella does not leak during baking, and start rolling.
Place the roulade on a baking paper in your baking sheet or just in the baking sheet greased with oil and spread a beaten egg on the top of the roulade.
Bake in a preheated oven at 375 °F / 190 °C for 25 minutes.