In a large mixing bowl, combine flour and salt. Cut in the butter until the size of small peas and mix in with your hands.
Mix 1/2 cup confectioners’ sugar, the egg, 3 teaspoons of vanilla sugar, and ground almonds into the flour mixture. Place the dough in the refrigerator for 30 minutes.
Preheat oven to 400 degrees F (200 degrees C). Line a baking sheet with parchment paper.
Divide the dough into several parts. Roll each section of dough into logs approximately 1/2 inch thick. Cut the logs into 1-inch pieces, and bend the pieces into a crescent shape (just like a croissant). Place the kipferl on the baking sheet and chill them for 15 minutes.
Bake in the preheated oven until the edges are golden brown, 10 to 15 minutes. Let cool slightly.
Combine 6 tablespoons confectioners’ sugar and 1 1/2 teaspoons vanilla sugar and toss to mix.
While still warm, carefully remove kipferl from the baking sheet and dip them in sugar to coat.