Preheat the oven to 400°F. Line a baking sheet with parchment paper.

Lightly sprinkle flour on a cutting board or clean flat surface. Spread the puff pastry sheet, and sprinkle it lightly with flour if required.

Roll out the puff pastry with a rolling pin until it is smooth and even.

Cut the puff pastry into triangles (approximately 6).

Place about ½ tablespoon of Nutella on the wide end of each triangle and spread it out slightly using a spoon if desired.

Starting with the wide end of the triangle, roll it tightly towards the narrow end to form a croissant shape. Use milk to seal the edge.

Place the rolled croissant on the lined baking sheet. Brush the top of each croissant with milk or egg wash.

Bake in the oven for 15-20 minutes, or until golden and flaky. Alternatively, air fry at 350°F for 15 minutes until golden and flaky.

Once cooled, dust with powdered sugar or drizzle with more Nutella or melted chocolate before serving.