Add the yeast and sugar to the warm milk, and stir well with a spoon until the yeast dissolves.

Add the flour, stir again, and leave in a warm place for 10-15 minutes until the starter rises into a fluffy foam - mine even started to overflow.

In a bowl, whisk the egg yolks, sugar, vanilla sugar, and salt until pale.

Pour in the starter and mix well. Add 2 cups of flour and the melted margarine, and whisk together - you'll get a thick dough.

Gradually adding the remaining flour (I used about 1 more cup), knead the dough by hand. Knead for a long time, about ten minutes: the longer you knead, the fluffier the bread will be.

Gather the dough into a ball, cover with plastic wrap, and leave in a warm place for 1 hour to rise.

Punch down the risen dough and cover with plastic wrap again in a warm place. Once the dough has risen a second time, add the poppy seeds and knead well again until smooth.

Grease the pans with vegetable oil and fill them 1/3 full with dough - I got two medium loaves. Leave in the pans for another hour so the dough rises about double.

Bake in an oven preheated to 180C for 30 minutes. Let the finished breads cool and remove them from the pans.

Whisk the egg white by hand, gradually adding the powdered sugar, until you reach the desired consistency. Add the lemon juice at the very end.

Generously pour the glaze over the breads - the more you use, the longer they'll stay soft - and sprinkle with decorations. Bon appetit!