Preheat the oven to 180°C top/bottom heat.
Grease three 18cm springform pans.
In a mixing bowl, mix flour, starch, cocoa, sugar, baking powder, and spices.
Add oil, quark, 150 mL of water, and apple cider vinegar and mix quickly by hand with a whisk.
Divide the batter between three greased 18cm baking pans and bake for 25 minutes.
Allow the chocolate bases to cool completely in the mold.
Meanwhile, prepare the dulce de leche (caramelized milk).
Caramelize the sugar in a saucepan over medium heat.
Add the cream while it is still hot and dissolve it.
If it does not dissolve completely, heat the cream again until a creamy caramel has formed.
For the cream filling, whip the cream until stiff.
Mix the cream stabilizer and sugar in a cup, then whip into the cream.
Season with a pinch of cinnamon.
Level the cake bases.
Start stacking the layers over a cake stand, alternating between whipped cream and dulce de leche.
Cover the cake with cream all over and chill for at least an hour.
Decorate with chopped hazelnuts and chocolate before slicing.