For the dough, mix the yeast with some sugar and a little bit of lukewarm milk, cover, and let rise from about 20 minutes.
Put the flour in a bowl and knead together with liquid butter, the rest of the sugar, eggs, the rest of the lukewarm milk, raisins, and the starter dough.
Beat the dough until it is soft and smooth.
Cover and let rise in a warm place.
Punch down and let rise again.
Now divide the dough into three ropes and make a braid.
Place on a buttered baking sheet and let rise again.
Preheat oven to 350 °F (180 °C).
Brush the braid with beaten egg and bake for 60 minutes.
Remove and let cool.
For the mousse, boil poppy with milk and then let cool.
Cream the butter and confectioner’s sugar, add the egg yolks, and beat more.
Chop up the chocolate, melt in a bain-marie, and fold into the butter with kirsch.
Finally, fold in the cooled poppy and whipped cream.
Fill a bowl with with mousse and chill for about 2 hours.
Cut the braided loaf into slices and serve with the poppy mousse.