Place almonds on a baking sheet and bake at 350° for 5-6 minutes. Cool slightly, then transfer to a food processor and grind until the almonds look like flour (do not over grind or they will become almond butter).

Add the flour, butter, salt, powdered sugar and vanilla sugar to the bowl of the food processor. Pulse until the dough comes together, about 2 minutes. Press the dough into a ball, wrap in plastic wrap, and chill for 45 minutes to 1 hour.

Preheat the oven to 350°. Line two baking sheets with parchment paper or a Silpat mat. Use a tablespoon to scoop up the dough and roll into a small log. Use your hands to shape each log into a crescent, then place onto the baking sheet, about an inch apart. Repeat until all of the dough has been used.

Bake cookies for 14 to 15 minutes, until the edges are just slightly golden (cookies should still be light in color). Cool on a cooling rack.

Combine the powdered sugar and vanilla sugar for the topping, then sift over the cookies until completely coated. Cookies can be kept in an airtight container on the counter for about 14 days.