Put the crumbled yeast in a mixing bowl. Warm the ALSACE LAIT semi-skimmed milk in a saucepan, pour over the yeast and stir with a whisk until the yeast has completely dissolved.
Put the flour, sugar, salt and whole egg in the bowl of a food processor with a kneading attachment, and knead for about 10 minutes until the dough is smooth.
Add the butter, cut into pieces, and knead again for 5 minutes. Shape into a ball and place in a mixing bowl. Cover and leave to rise for 1 hour 30 minutes.
Flour your work surface and knead the dough to remove any air bubbles. Divide the dough into three pieces. Using a rolling pin, shape three rectangles.
Cover with the hazelnut chocolate spread.
Roll each rectangle into a long sausage and plait them together. Line a cake tin with baking paper.
Place the plait in the tin and leave to rest for 30 minutes.
Preheat the oven to 180°C.
Mix an egg yolk with a little ALSACE LAIT semi-skimmed milk.
Brush the plait with this mixture.
Sprinkle with chopped hazelnuts.
Bake in the oven for 30 minutes.
Enjoy!