Prepare the Dough
In a bowl, mix warm milk, sugar, and dry yeast. Let it sit for 10 minutes until foamy.
Add flour, melted butter, egg yolks, salt, and vanilla extract. Knead until smooth.
Cover and let rise for 1.5 hours, or until doubled in size.
Make the Filling
Grind the poppy seeds in a coffee grinder or food processor.
Mix with honey, powdered sugar, and lemon zest until combined.
Assemble the Roll
Roll out the dough into a rectangle on a lightly floured surface.
Spread the poppy seed mixture evenly over the dough.
Roll it up tightly into a log and place it on a lined baking sheet. Cover and let rise for another 30 minutes.
Bake
Preheat oven to 180°C (350°F).
Bake for 30-35 minutes, until golden brown and firm to the touch.
Drizzle with Chocolate
Melt dark chocolate with heavy cream over low heat, stirring until smooth.
Drizzle over the cooled roll and let set before slicing and serving.