Knead 100 g butter in pieces, 50 g sugar, flour, egg and salt to a short pastry. Cover and chill for about 30 minutes. Meanwhile bring 400 g sugar, lemon juice and 250 ml water to the boil while stirring and boil until the syrup caramelises. Remove the pot from the heat, add the sour cream and stir evenly. Add nuts, except for 10 nice halves, and stir in.
Cut 200 g butter into cubes, add to the caramel and stir until the butter has melted and combined with the caramel mass. Let the nut caramel cool down to room temperature. Grease the tart mould (26 cm Ø). Roll out the dough round (approx. 30 cm Ø) on a work surface dusted with flour. Line the tart mould with the dough, cut off any protruding edges. Pour the caramel into the mould and spread evenly. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 35 minutes. Let the tart rest on a cake rack for about 10 minutes. Remove from the mould and leave to rest overnight in a cool place. (Caramel mass can be cut better this way).
Pour the caramel into the mould and spread evenly. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 35 minutes. Let the tart rest on a cake rack for about 10 minutes. Remove from the mould and leave to rest overnight in a cool place. (Caramel mass can be cut better this way). Decorate the cake with the remaining walnuts and cut into pieces. Serve with a sour cream dip
12 hours waiting time. Per piece about 1590 kJ/380 kcal. E 4 g/F 27 g/KH 30 g