Preheat your oven to 200°F (95°C), then turn it off but keep the door closed.

In a large mixing bowl, whisk together the flour, yeast, poppy seeds, and salt.

In another bowl, combine the buttermilk, sugar, and melted butter, mix with dry ingredients, then add eggs and lemon zest to form a soft dough.

Knead the dough on a floured surface for 5-7 minutes, form into a ball, place in a greased bowl, cover with a towel, and allow to rest for 10-20 minutes.

Mix granulated sugar, brown sugar, and lemon zest in a bowl, then add softened butter to create a smooth filling.

Roll the rested dough into a 12x18 inch rectangle, spread the filling, and tightly roll it into a log.

Cut the rolled dough into 12 pieces using dental floss and place in a greased baking pan, covered with foil.

Let the rolls rise in the turned-off oven for 30 minutes.

Preheat the oven to 350°F (175°C) and bake for 28-32 minutes until golden brown.

Whisk together powdered sugar, lemon juice, and melted butter until smooth to prepare the icing.

Cool the rolls for 10-20 minutes, then drizzle with icing and add fresh lemon zest if desired.