In a small bowl, dissolve the yeast in the warmed milk and let it sit for about 5 minutes until foamy.
In a large mixing bowl, combine the flour, sugar, and salt. Cut in the softened butter until the mixture resembles coarse crumbs.
Add the yeast mixture and eggs to the flour mixture. Mix until a dough forms. Knead the dough on a floured surface for about 5-7 minutes, or until smooth and elastic.
Place the dough in a lightly greased bowl, cover with a clean cloth, and let it rise in a warm place for about 1 hour, or until doubled in size.
In a saucepan, combine the poppy seeds and milk. Bring to a boil, then reduce heat and simmer for about 10 minutes, or until the mixture thickens.
Remove from heat and stir in the sugar, honey, butter, vanilla extract, and cinnamon. Mix well until smooth. Add raisins and walnuts if using.
Preheat your oven to 350°F (175°C). Grease a loaf pan or line it with parchment paper.
Punch down the risen dough and roll it out on a floured surface into a rectangle.
Spread the poppy seed filling evenly over the dough, leaving a small border around the edges.
Roll up the dough tightly from the long side to form a log. Pinch the ends and seam to seal.
Place the rolled dough seam-side down in the prepared loaf pan.
Bake for 30-35 minutes, or until golden brown and a toothpick inserted into the center comes out clean.
While the cake is baking, prepare the glaze by mixing the powdered sugar with enough milk to achieve a drizzling consistency.
Let the Makowiec cool completely before glazing.
Drizzle the glaze over the cooled Makowiec and let it set before slicing.
Enjoy your meal!