* Preheat the stove to 200 degrees.
* Rinse, clean and chop the radicchio.
* Cut puff pastry into about 10 larger squares (about 15 centimeters on a side) and form equal parts of radicchio and fresh salmon in the center.
* Season with salt and pepper.
* Close the puff pastry by folding all four corners inwards, press briefly until smooth and brush with egg yolk.
* Bake the filled puff pastries on the middle rack for about 20 minutes until crispy.