For the vanilla slices, mix 2 tablespoons of powdered sugar with vanilla sugar. Crumble butter and sugar, knead with salt, vanilla pulp and flour. Let rest in plastic wrap in a cool place for 1 hour.
Roll out between cling film, cut out discs 3 cm in diameter and place on a coated baking tray. Bake in preheated oven at 200° for about 8 minutes.
When cooled, assemble with jam and sprinkle with sugar-vanilla sugar mixture.