Again, In a saucepan, combine the milk and sugar over medium heat. Keep heating until it comes to a boil. Turn off the heat and remove the pan from the heat. Add the ground poppy seeds, the raisins and the lemon zest. Mix the ingredients properly and let them be cooled.
Preheat your oven to 180°C (355°F). Then take the pan and line it with parchment paper.
Roll out each piece of dough on a floured surface into a rectangle that is approximately 12×14 inches (30×35 cm).
Use a spoon to place the walnut or poppy seed filling on top of the dough. The edges should be empty approximately half an inch. Then roll up the dough lengthwise. The rolls should not be too tight or too loose. Gently place the rolls onto the baking sheet.
Take egg yolks in a small bowl and gently whisk them. Brush the top of the four rolls with a soft-bristled brush. Let them sit for about 30-40 minutes. Once the egg yolk has dried, brush on a layer of egg white. Let it dry in a cool place; if possible, not in the fridge.
Make small holes in the top of the rolls with a skewer so steam can escape and prevent the pastry from splitting.
Bake for about 30-35 minutes or until golden brown.
Prior to serving, store the rolls in a cool and dry place and slice them.