Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
Unroll the puff pastry and cut into 6 equal rectangles.
Place a piece of chocolate and a banana slice in the center of each rectangle.
Fold the pastry over the filling and press the edges with a fork to seal.
Brush the tops with egg wash.
In a small bowl, mix sugar and cinnamon, then sprinkle on top of each pastry.
Bake for 15–18 minutes or until golden brown.
Let cool slightly and serve warm.