1Heat oven to 400°F. In large bowl, mix butter, 1/2 cup powdered sugar, the vanilla and egg. Stir in Bisquick mix and nuts until dough holds together.
2Shape dough into 1-inch balls. On ungreased cookie sheets, place balls about 1 inch apart.
3Bake 9 to 11 minutes or until set but not brown. Immediately remove from cookie sheets to cooling racks. Cool slightly.
4Roll warm cookies in powdered sugar; place on cooling racks to cool completely. Roll in powdered sugar again.