Begin by placing one sheet of the thawed puff pastry on a surface lined with non-stick paper. Gently roll it out a little with a rolling pin. Place a 26 cm plate on the center of the puff pastry and cut around it to form a circle, removing any excess pastry. Evenly spread the hazelnut praline over this circular pastry.
Cut the second sheet of puff pastry to match the size of the first and carefully place it over the layer of hazelnut praline. Center a smaller plate on top of this pastry stack and cut around it to make 16 evenly spaced radial slices, ensuring the center remains intact to hold the shape together.
Take two adjacent pastry slices and twist them in opposite directions three times. Pinch the ends together to form a point, resembling a star's arm. Repeat this process for all the slices.
In a small bowl, beat the egg and brush this egg wash over the pastry. Bake in a preheated oven at 200°C (392°F) for 25-30 minutes, or until the puff pastry turns a golden brown. Allow the pastry to cool slightly before sprinkling with powdered sugar. Serve this festive treat warm.