Put the milk, curd cheese, yeast, sugar, flour, eggs, yolk, salt, lemon zest and vanilla in a bowl and knead until the ingredients are well combined.
Add the butter in pieces, and knead until a smooth dough is formed.
Knead in the raisins briefly (optional).
Cover the dough and leave to rise in a warm place, for 1 to 1½ hours.
Divide the dough in half and form each into 4 or 6 strands.
Braid into a plait. See video.
Place the plaits on a baking tray, cover and leave to rise, for about 60 minutes.
Brush with the egg yolk and milk mixture.
Sprinkle with pearl sugar.
Bake in preheated oven at 160° C for about 40 to 45 minutes. Halfway through the baking time, cover with aluminium foil to prevent it from getting too dark.