1In a bowl, crumble yeast, add a little milk (1or 2 tablespoons) to dilute it, with a teaspoon of sugar.
2Mix, and let it stand for 5 minutes.
3Pour in food processor bowl with butter, flour, and eggs.
4Mix dough for 5 to 7 minutes to obtain a uniform ball of dough. Cover the bowl with a dry cloth or plastic film. Let rise for 45 minutes, in a warm place, free of drafts.
5Bring milk to boil in a saucepan. add ground poppy. Let stand for 10 minutes.
6Mix butter and sugar, and then add the egg. Add to milk mixture. Stir, and set aside.
7Preheat oven to 180 degrees Celsius.
8Roll dough out on a lightly floured surface to form a rectangle 35 x 40 centimeters. Use a knife or a spoon to spread and cover dough with poppy mixture.
9Roll dough tight (like a jelly roll). Cut roll in half, and wreathe the 2 parts together. Cut the 2 ends to get a clean edge and gather them to form a crown.
10Brush with egg yolk diluted in 1 tablespoon of milk.
11Bake for 30 minutes until golden.
12Remove from oven. Cool.
13Prepare icing by mixing lemon juice and powdered sugar (amounts depend on desired consistency).