• Solve the fresh yeast in a bit of lukewarm milk. It's a traditional step to ensure the yeast is working. If we trust our yeast, it can be sprinkled directly onto the flour but adding milk or water to the flour is necessary too.
• Mix flour with the butter and sweetener.
• Add the yeast and milk if haven't been added before.
• Work in the egg yolks, rum, sour cream, lemon zest and salt too and dough until getting an even texture.
• Put dough into a big bowl with a lid on top and let it rest. Ideally overnight in the fridge but if short on time just let it raise for an hour on room temperature or in a 100°F / 40°C oven.

Walnut filling:

• Mix all the ingredients together and let it sit in the fridge until the dough is ready.

Poppy seed filling:

• Mix all the ingredients together in a saucepan.
• On the stove top bring the milk to boil in low temperature while stirring continuously.
• Take it off the heat and cool it down otherwise it will ruin the dough. Place it next to the walnut filling until waiting for the dough to raise.

Assembly:

• Dust the work surface with flour then divide the dough into 4 parts.
• Butter the baking tray or cover it with parchment paper.
• Work with one piece at a time roll out the dough into a 1/8" / 3mm high rectangular shape the length of our baking tray.
• Choose the first filling and fill half of it along one of the long side of the dough. Mind to leave an empty stripe on one side otherwise the dough can't be closed properly.
• Roll the dough up.
• Place them into the buttered or parchment papered baking tray.
• Repeat until the filling and dough runs out which should be after 3 more nut rolls.
• Brush the top with eggwash and punch holes alongside with a fork.
• Place them into a 350°F / 180°C preheated oven for about an hour. (330°F / 165°C for convection ovens)
• After about an hour it should come out with a golden brown top and tantalizing smell. Don't resist it!