For the sour cherry cake, use a cake springform pan with 280 mm ø.
Cream the butter with the sugar until white and fluffy. Add the hazelnuts, egg, flour and cinnamon and stir everything together to form a dough. Wrap the dough in plastic wrap and chill for min. 30 minutes.
Remove the seeds from the sour cherries.
Butter the cake springform pan and dust with flour. Preheat the oven to 180 °C.
Spread 2/3 of the dough directly on the springform pan bottom about five mm thick. Roll out the remaining dough into a finger-thick roll. Place the edge of the mold, place the dough rolls along the edge and pull them up a little. Then place the sour cherries on the dough.
Bake the sour cherry cake at 180° Celsius on the second lowest rack for 40 minutes. Let the cake cool, if the sour cherries are too sour, sprinkle a little sugar over them.