Knead the flour, icing sugar, salt, 125 g butter and egg first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Wrap dough in foil and chill for approx. 30 minutes
Peel and quarter apples and cut out the core. Quarter the apples again lengthwise and sprinkle with lemon juice. Roast the hazelnuts in a pan without fat. Take out, let cool and put 1 tbsp aside for decoration. Rinse and drain the sultanas
Grease the tart mould (24 cm Ø). Caramelise the sugar and 3 tbsp. water of a pan until golden brown. Add 20 g butter, melt and pour the caramel on the bottom of the tart mould. Spread apple slices fan-shaped on the caramel. Sprinkle with hazelnuts and sultanas
Roll out the dough on a floured work surface slightly larger than the form. Place the dough on the apples. Carefully press the protruding edges of the dough down into the mould. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 25 minutes. When still hot, turn out of the pan and let it cool down a little. Sprinkle with remaining hazelnuts. Whipped cream tastes good with it
Waiting time approx. 30 minutes