Finely chop the candied lemon peel and candied orange peel. Mix flour and dry yeast in a bowl. Add milk, melted fat, sugar, salt, candied lemon peel and candied orange peel and knead ingredients to a smooth dough.
Cover the dough and let it rise in a warm place for about 30 minutes. Knead the Stollen dough again well and divide it into three equal pieces. Roll out each piece on a floured work surface to a strand 30 centimetres long and ten centimetres wide.
Spread the poppy seed mixture over the middle of the strands. Fold the dough over the filling and form each piece into an even roll. Weave the dough strands into a braid. Place the Stollen plait on a baking tray lined with baking paper and brush with the whisked egg yolk.
Cover and leave to rise again for 20 minutes in a warm place. Bake in the preheated oven (electric: 175 °C/ gas: level 2) for 40 minutes. Heat up the jam and pass through a sieve. Brush the hot stollen with the jam.
Mix the poppy seeds and icing sugar and sprinkle over the plait as it follows the plait pattern. Let the poppy seed stollen cool on a grid and store it well packed. Makes 25 pieces.