Preheat oven to 350°F. Line two baking sheets with parchment.
Toast pecans on a sheet for 6–8 minutes until fragrant. Cool, then chop very fine.
Cream butter and the powdered sugar for the dough until light and smooth.
Beat in vanilla and salt until evenly combined.
Add flour in two additions, mixing just until a soft dough forms.
Fold in chopped pecans. Chill the dough for about 20 minutes to firm slightly.
Scoop level tablespoons of dough, roll into 1-inch balls, and space 2 inches apart on sheets.
Bake 12–14 minutes until set and just turning golden on the bottoms, not browned on top.
Cool on the sheet for 5 minutes, then gently roll warm cookies in coating sugar.
Transfer to a rack to cool completely, then roll once more for a snowy finish.