In a food processor, combine the walnuts and powdered sugar.
Cube the frozen butter and add it to the ground walnuts and sugar along with the flour. Blitz until combined. Then add the vanilla extract and salt. Combine again.
This should yield a crumbly mixture that just barely holds together. If its too dry feel free to add a splash of milk
Lightly dust a work surface (or cutting board) with flour and roll the “dough” into a log shape about 1 inch in diameter. Wrap the log in plastic and chill in the fridge for at least 1 hour
Preheat oven to 350°F.
Remove the dough logs from the fridge and slice into disc about 1/4 inch thick. Then shape these into crescents and place on a parchment paper lined baking sheet. Bake for 12-15 minutes. They should not brown.
Remove from heat and let cool. Dust with powdered sugar and enjoy!