In a large mixing bowl, combine the warm milk and active dry yeast. Let it sit for about 5 minutes until it becomes frothy.
Add 1/4 cup of granulated sugar and the three large eggs to the yeast mixture. Whisk everything together until well combined.
Gradually add in 1 cup of all-purpose flour, mixing until smooth. Then, stir in the melted butter and salt. Once incorporated, gradually add the remaining 5 cups of flour. Mix until the dough comes together.
Transfer the dough onto a lightly floured surface. Knead it for about 8-10 minutes until it becomes smooth and elastic.
Place the kneaded dough in a greased bowl, cover it, and let it rise in a warm place for about 1 to 1.5 hours, or until it doubles in size.
While the dough is rising, prepare your poppy seed filling.
Once the dough has risen, punch it down, divide it into equal pieces, roll each piece into a circle, and add a spoonful of filling in the center.
Place the filled buns on a greased baking sheet, cover them, and let them rise again for about 30-45 minutes.
Preheat your oven to 350°F (175°C).
Brush the tops of the buns with the beaten egg wash and sprinkle with dry poppy seeds. Bake for 20-25 minutes, or until golden brown.
Once baked, remove the buns from the oven and allow them to cool slightly on a wire rack. Serve warm.