Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper.

Gently unfold one sheet of the thawed puff pastry onto a lightly floured surface.

Using a sharp knife or a pizza cutter, cut the puff pastry sheet in half lengthwise. Then, cut each half into 3-4 triangles.

Sprinkle a generous amount of chocolate chips (about 1-2 tablespoons) near the wide base of each triangle.

Starting at the wide end, gently roll up each triangle towards the point, forming a crescent shape.

In a small bowl, whisk together the egg and water until well combined to create the egg wash.

Place the rolled croissants onto the prepared baking sheet, leaving a little space between each one. Brush the tops of the croissants with the egg wash. If using, sprinkle coarse sugar over the egg wash.

Bake for 15-20 minutes, or until the croissants are golden brown and puffed up.

Let the croissants cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.