Put the milk, butter, sugar and yeast in the mixing bowl and heat for 2 min / 37 ° C / speed 2. Add flour, egg and salt and knead the dough 3 min / speed. Transfer the dough and let it rise in a warm place for about 30 minutes.
Filling:
Pour the hazelnuts and chocolate into the mixing bowl and chop 6 sec / speed 8. Add apples, sugar and cinnamon and chop 5 sec / speed 8. If the mixture is too firm, mix in 50 g of milk.
Roll out the dough thinly into a rectangle (approx. 5060 cm). Spread the filling evenly on top. Fold in the narrower sides a bit. Roll up from the long side. Halve the roll lengthways so that you have two long, open strands. Lay both strands on top of each other like a St. Andrew`s cross with the cut surface facing up. Braid the open strands towards the end. Place the looped dough as a wreath on a baking sheet lined with baking paper and brush with milk.
Let rise for another 15 minutes and bake in a preheated oven at 200 ° C for about 10 minutes. Then reduce the baking temperature to 180 ° C and bake for another 40 minutes.