2 cups California walnuts toasted
2 cups all-purpose flour
3/4 teaspoon salt
1 cup (2 sticks) unsalted butter, softened
1/3 cup granulated sugar
1-1/2 teaspoons vanilla extract
1-1/2 cups powdered sugar
Adjust two oven racks to the upper middle and lower middle positions of the oven and preheat to 325℉. Line two baking sheets with parchment paper or silicone mats.
In a food processor, finely grind 1 cup walnuts, about 10 to 15 seconds. Transfer to medium bowl.
Pulse the remaining 1 cup walnuts in food processor, about 5 seconds. Add to the medium bowl containing finely ground walnuts. Stir in flour and salt and set aside.
Combine butter and granulated sugar in bowl for electric mixer. Beat 2 minutes or until fluffy. Scrape sides of bow. Add vanilla; beat 1 minute.
Add flour and walnut mixture; beat 30 seconds or until combined. Scrape down the sides of bowl and beaters and continue to hand mix the dough until well combined.
Working with 1 tablespoon of dough at a time, roll into 1-1/4-inch balls and arrange 1 inch apart on prepared baking sheets. Bake until cookies are lightly golden brown, about 18 minutes, rotating baking sheets after 9 minutes.
Remove cookies from oven and cool on baking sheets for 10 minutes. Transfer to a wire rack; cool completely. Roll cookies in powdered sugar.
Just before serving, re-roll cookies in powdered sugar. Gently shake to remove the excess.