Lay out the tortilla and evenly apply the hazelnut chocolate spread.
Peel and slice the banana, then lay it out on top of the chocolate hazelnut spread.
Fold the tortilla bottom-up first then fold in either side. Place fold side down on the preheated grill to hold it together.
When there are browned grill grate markings, turn and cook the other side until it too has golden brown grill grate marks. By this stage, the inside will also be heated and the bananas softened.