With electric mixer, cream butter well. Add sugar, vanilla extract and salt; continue creaming. Beat in hazelnut meal, then beat in flour. Scrape out onto a piece of waxed paper or plastic wrap, shape into a disk, wrap and chill for about 30 minutes.
Preheat oven to 350°F. On a very lightly floured surface, roll or pat dough into 1/4-inch-thick 7 1/2 inch square. Cut into 25 - 1 1/2 inch squares. Place on parchment-lined baking sheet.
Bake at 350 degrees for about 16 to 18 minutes; edges will be just barely starting to brown.
