Preheat the oven to 325°F (165°C) and line a baking sheet with parchment paper.
Toast the Blanched almonds on the prepared sheet for 8–10 minutes until lightly golden; let cool and chop finely or pulse to a coarse meal.
In a large bowl, cream the Unsalted butter with half of the Powdered sugar until pale and fluffy. Add the Egg yolk, Vanilla extract, Brandy and Rosewater and beat until well combined.
Whisk together the All-purpose flour, Baking powder and Salt in a separate bowl, then gently fold the dry mixture and the chopped toasted almonds into the butter mixture until a soft dough forms.
If the dough feels very soft, chill it for 20–30 minutes to make shaping easier. Shape the dough into small crescents or round mounds, placing them on the prepared baking sheet about 1 inch apart.
Bake for 15–20 minutes, or until the cookies are set and just beginning to show a very light golden edge — they should remain fairly pale. Remove from the oven and let cool on the sheet for 5 minutes.
While still slightly warm, gently roll each cookie in additional powdered sugar to coat; transfer to a wire rack to cool completely. Once fully cooled, dust the cookies again with more powdered sugar for the classic snowy finish.
Store in an airtight container; the cookies will mellow and become even more fragrant after a day.
