Stir yeast with 1 tablespoon of sugar until liquid. Warm 200 ml milk lukewarm. Knead 500 g flour, 80 g sugar, yeast, milk, 1 egg and butter with the dough hooks of the mixer to a smooth dough. Cover and leave to rise in a warm place for about 1 hour until the dough volume has doubled.
Line a baking tray with baking paper. Whisk 1 egg and 2 tbsp. milk. Knead the dough again well, then quarter it. Form each quarter into a ball and roll out one after the other in circles (approx. 25 cm Ø) on a floured work surface.
Put the first circle on the plate. Warm the nut nougat cream to lukewarm. Spread approx. 1⁄3 on the circle, leaving a rim of approx. 2 cm. Spread a thin layer of egg milk on the edge. Do the same with 2 more circles, always pressing the edges lightly.
Cover with the last circle.
In the middle of the circle, turn a glass (approx. 7 cm Ø) upside down and press it slightly into the dough so that a circle is clearly visible. Cut the dough around the circle into 16 cake pieces and twist each piece twice.
Press the ends of 2 adjacent cake pieces together. Cover the star and let it rise in a warm place for another 30 minutes.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Coat the surface with the remaining egg milk and bake the star in the hot oven for approx. 30 minutes.