Knead the butter in pieces, flour, egg, 80 g sugar and 2 tbsp water first with the dough hook of the hand mixer, then with your hands to a smooth dough. Roll out 3/4 of the dough on a thinly floured work surface (approx. 28 cm Ø). Grease a pie mould (19/23 cm Ø) and line it with it. Place the mould in a cool place for approx. 30 minutes.
Wash the cherries, put some aside for decoration. Stone and destem the rest. Mix cherries, 30 g sugar, starch and cinnamon. Sprinkle the pastry base with hazelnuts. Add the cherry filling
Roll out remaining dough into an oval shape and roll over with a grid roller and roll over a dough roller, roll over the cherry filling and carefully pull apart. Press the edges firmly. Mix the egg yolk and cream and brush the dough with it. Sprinkle with 1 tsp. sugar and bake in the preheated oven (electric oven: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 1 hour until golden brown. Remove and let cool off. Decorate with remaining cherries
waiting time approx. 2 1/4 hours