Preheat the oven to 350°F (175°C) and line baking sheets with parchment paper.
Prepare the vanilla sugar by splitting the vanilla beans lengthwise and scraping out the seeds.
Combine the vanilla bean seeds with 1/2 cup plus 1 tablespoon of white sugar in a bowl, mixing well; set aside to infuse.
In a large mixing bowl, cream together the softened butter and white sugar (1/2 cup and 2 tablespoons) until light and fluffy.
Add the egg yolks one at a time, mixing well after each addition.
Fold in the all-purpose flour and almond flour gradually until the dough comes together into a smooth, pliable ball.
Divide the dough into small portions and roll each into crescent-shaped cookies approximately 2-3 inches long.
Place the shaped cookies on the prepared baking sheets with space in between.
Bake in the preheated oven for 12-15 minutes, or until the edges are lightly golden but the cookies remain pale.
Remove from the oven and allow the cookies to cool slightly on the baking sheet for 5 minutes.
While still warm, gently roll each cookie in the prepared vanilla sugar to coat thoroughly.
Transfer the cookies to a wire rack to cool completely; store in an airtight container to keep fresh.