(The black one is filled with finely ground poppy seeds and sugar.)

The secret is a good yeast-dough with lots of eggs and butter. Adding two generous tablespoons of plain yoghurt also helps the yeast and leads to a fluffy dough.

And after filling the dough, right before backing, give it another half an hour to rise.

Can I ask you, what filling was used on the right side nut rolls? Is that a walnut filling?

I've never made this type of pastry, but I've eaten it many times. I'm more likely to make the Baklava-type of layered pastry (using fillo dough) but I'm marvelling at your photo. Maybe I'll give this a try.

I'm unfamiliar with what a Hungarian nut roll is, but I'll try anything once. (Have you tried butter?)