For the dough, mix 1 pinch of salt, 50 g sugar, butter cubes, 1 egg and possibly cold water with the dough hook. Knead with your hands. Put the dough as a ball, wrapped in foil, in a cool place for 30 minutes.
Preheat the oven to 200 ° C top / bottom heat (convection: 180 ° C).
Roll out the dough, place in a greased cake tin (26 cm diameter) and shape the edge. Crumble the shortbread biscuits finely, mix with the hazelnuts and sprinkle on the dough base. Rinse and dab blueberries and mix with lime juice, lime zest and 50 g sugar. Distribute in the mold.
Pre-bake in a hot oven for about 15 minutes.
Mix 4 eggs with cream, cornstarch and 50 g sugar. Pour the icing over the berries and bake for another 20-30 minutes.