Prepare the yeast dough and let it rise for about 40 minutes.
Line a baking tray with baking paper. Briefly knead the yeast dough on a little flour, cut in half. Roll out each half to a narrow rectangle (approx. 18 x 75 cm). Spread with plum puree, leaving a 3 cm wide edge on the upper long side.
Thinly brush the edges with water. Roll up rectangles from the lower long side. Press the edges of the seam well.
To weave, place the dough rolls in the middle of each other as a cross. Place both ends of the lower dough roll on the other side. Do the same with the bottom roll of dough. Repeat the process until the dough is completely braided.
Press the ends of the braids well together and place under the braid. Lift onto the tray. Cover and leave to rise in a warm place for about 20 minutes.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Whisk the egg yolk and milk and brush the plait with it and sprinkle with rock candy. Bake in the hot oven on the second rack from below for approx. 25 minutes.
After 15-20 minutes, cover with aluminium foil if necessary. Take out yeast plait and let it cool down.