To remove the bitterness from poppy seeds, place ground poppy seeds in a large bowl and pour boiling water over top. Let them sit in the boiling water for 20 minutes, then drain through cheesecloth. Air dry in the cheesecloth by tying all the corners together and hanging it over a bowl. Leave for 60 minutes.
The Dough
In a small mixing bowl, dissolve in ½ cup warm water, 7 g active dry yeast, and 1 tsp. sugar. Stir and leave to foam on top for 5-10 minutes. If it doesn't foam, repeat again with new yeast.
In a large mixing bowl, sift the 460 g all-purpose flour and make a well in the middle. Add the yeast mixture and the 100 g sugar, ¼ tsp. salt, 75 g unsalted butter, 1 egg, ⅔ cup warm milk and 1 tsp. vanilla extract. Mix with a large wooden spoon then transition to mixing with your hands. Stop mixing as soon as a soft dough forms.
Let rise until doubled, 45 minutes in a warm place.
The Filling
While waiting for the dough to rise, combine 200 g poppy seeds, 200 g sugar, ¼ tsp. salt and 1 cup milk in a medium saucepan. Heat on low-medium heat until mixture thickens.
Add cold 75 g unsalted butter, 1 tsp. vanilla extract, ¼ tsp. almond extract, chopped 100 g walnuts and 40 g breadcrumbs. Stir until smooth. Add the whisked 1 egg and stir. Set aside in refrigerator while waiting for the dough.
The Rolling
When the dough is done, punch it down the dough and mix to incorporate any uneven bits. Cut dough into two pieces.
Dump one half onto a lightly floured work surface. Sprinkle with flour and roll into a large, thin rectangle.
Spread half the filling onto the rolled dough, leaving a 1" border all around. Roll the dough starting from the long edge. Pinch and tuck the ends under the roll. Quickly and carefully transfer onto large parchment lined baking sheet.
Repeat with the second half of dough and filling. Transfer it next to the other roll on the baking sheet, leaving a few inches of space in between. Let rise for 30 minutes or until increased in size and puffy.
The Cooking
Preheat oven to 350℉. While it is preheating, create your egg wash by whisking 1 egg and 1 Tbsp. milk until smooth. Brush on top of the rolls, covering all exposed surfaces. Lightly sprinkle the top with extra poppy seeds.
Bake in preheated oven for 40-50 minutes, checking every 5 minutes after 40 minutes. The top will be golden brown.
The Serving
Let the Poppy Seed Rolls cool in the pan, cut into slices and enjoy!