Preheat your oven to 200°F (95°C) and gather a large mixing bowl. Mix together flour, yeast, poppy seeds (if using), and salt.

Combine buttermilk, sugar, and melted butter in a separate bowl. Microwave for about 30 seconds until warm, then stir gently to blend.

Gradually pour the buttermilk mixture into the dry ingredients and add large eggs one at a time, mixing until a sticky dough forms.

Incorporate the fresh lemon zest and add flour, a tablespoon at a time, until the dough is tacky but pulls away from the sides.

Cover the bowl with a kitchen towel and let the dough rest for 10-20 minutes in the warm oven until slightly puffed.

Prepare the filling by mixing sugar and lemon zest in a small bowl, then blend in softened butter for a smooth paste.

Roll out the rested dough into a rectangle approximately 12x18 inches and spread the lemon filling evenly across it.

Starting from one long end, tightly roll the dough into a log and cut into 12 even pieces using dental floss.

Cover the pan with a towel and let the rolls rise for another 30 minutes until noticeably puffy.

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

Mix powdered sugar, lemon juice, and melted butter in a small bowl until smooth, then set aside while rolls bake.

Once baked, let rolls cool for 10 minutes in the pan, then drizzle icing generously over the warm rolls.