A white wine that brilliantly accompanies the saltiness of the bacon in the quiche.
Cube chilled butter. Pulse the flour, cold butter, egg yolk, and a pinch of salt together with a little cold water until a smooth dough forms. If dough seems too dry, add more cold water a little at a time until dough comes together. Cover for approx. 30 min. with plastic wrap and refrigerate.
Preheat oven to 200°C/400°F. Wash leeks and cut into rings. Core and dice apples. Finely chop hazelnuts and set aside. Mix together the eggs and sour cream and season with salt and pepper.
Heat oil in a large frying pan set over medium-high heat. Fry the bacon, leeks, and apples together until bacon until browned and fragrant.
Roll out chilled quiche dough between 2 layers of plastic wrap into a circle approx. 28 cm/11 in. in diameter.
Grease the tart pan and transfer dough to the pan. Gently press dough evenly into corners and up sides. Add the apple, leeks, and bacon to pan. Sprinkle half of the hazelnuts on top, then top with egg mixture.
Sprinkle with the remaining hazelnuts and bake for approx. 35 min. at 200°C/400°F. Allow to cool and enjoy!