Knead nuts, flour, icing sugar, cocoa, cinnamon, fat and egg until smooth. Cover and chill in the freezer for 10 minutes
Line 2 baking trays with baking paper. Roll out the dough on a little flour to a thickness of about 3 mm. Cut out a total of approx. 60 hearts (approx. 5.5 cm Ø). Cut out smaller hearts (approx. 3 cm Ø) from half of the hearts and use as dough remains. Place whole hearts and hearts with hole on the trays. Bake in a hot oven (electric cooker: 200 °C / convection oven: 175 °C / gas: level 3) for 10-12 minutes. Let them cool down
Warm the jam and pass through a sieve. Coat whole hearts with it. Place hearts with a hole on top, dust the edges with icing sugar. Fill the holes with jam