Cut the butter into pieces. Put 100 g sugar, flour and egg in a mixing bowl. Knead first with the dough hooks of the hand mixer, then quickly with your hands to a smooth short pastry. Wrap the dough in foil and chill for about 30 minutes. Roll out the dough on a floured work surface to a thickness of approx. 0.5 cm and cut into strips of approx. 3.5 cm. Cut the strips into approx. 6 cm long rhombs. Place on 2 baking trays lined with baking paper and bake one after the other in a preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 15-20 minutes.
Let them cool down. In the meantime cut the macadamia nuts in half. Cook 300 g sugar with 2 tablespoons of water at medium heat in a pan to a golden brown caramel. Add cream and simmer until the sugar is dissolved. Add nuts to the caramel. Quickly spread the nut caramel with 2 tablespoons on the cookies and let it dry