Cut one sheet of puff pastry into two parts each. Flatten and place one piece of banana, slices of cheddar cheese, and about 1 tablespoon of chocolate sprinkle at the center of the dough, pinch to seal, and gently shape it.
Place into a baking pan.

Preheat oven 180 °c. Brush the top of puff pastry with egg wash (1 egg + 1 teaspoon oil, mix together), or water or milk wash (just some milk). And sprinkle with chocolate and Bake in preheated oven for 20-25 minutes, or until golden brown.