Mix well butter and powdered sugar until creamy. Mix in salt and vanilla. Slowly incorporate the flour, then the ground hazelnuts.
Shape dough into 2-inch crescents, using 1 Tbsp. dough for each. Place, 2 inches apart, on parchment- or foil-covered baking sheets.
Bake 12 to 15 min. or until lightly browned. Cool on baking sheets 2 min. Remove to wire racks; cool completely.