Make the croissants as described in the instructions. Place them a baking tin, in line. Brush their surface with egg yolk and sprinkle with sugar. Bake them in a preheated oven at 200°C for 25 minutes.

For making Crescent Rolls:
Cut each puff pastry sheet into 4 squares. Cut each square diagonally, into 2 parts. Whisk the egg whites, brush each triangle and sprinkle with a little sugar before adding the filling. Crumble the dark chocolate into small pieces. Add a teaspoonful of the hazelnut praline and a little grated dark chocolate in the middle of the short vertical side of each triangle. Carefully wrap the short vertical side of the triangle inwards. Continue to wrap until you reach the top of the triangle. Curve the ends inward to give the crescent shape.