Put the flour, sugar, salt, vanilla pulp and ground hazelnuts in a bowl. Add flakes of fat and egg yolk. First work through everything with the dough hook of the hand mixer, then knead with your hands to form a smooth dough. Chill for about 1 hour.
Shape the dough into a roll of approx. 2 cm. Cut the roll into approx. 1 cm thick slices. Shape slices into balls and place on a baking sheet lined with baking paper. Make a small depression in each cookie with a lightly floured wooden spoon handle. Bake in a preheated oven at 200 ° C for about 12 minutes. Let cool down.
Dust the cookies with the powdered sugar. Heat the jelly, stir until smooth and pour into the wells with a teaspoon. Let the quince jelly dry.