Preparation

1. Preheat oven to 350 degrees.
2. Spread the hazelnuts on a straight sided parchment lined baking sheet and roast them until fragrant, about 12-14 minutes. Remove from oven and place nuts on a clean kitchen towel. Rub the hazelnuts in the towel to remove the skins. If a few stay on, that is okay. Allow the hazelnuts to cool before coarsely chopping them. Set parchment lined baking sheet aside. Reduce the oven temperature to 325 degrees.
3. Add the egg whites to a medium bowl. Using a handheld mixer(or standing mixer) beat the egg whites on high speed until light and fluffy, about 1 minute. Add the sugar, salt and vanilla and beat again until medium peaks form, another 4 minutes. Fold in the chopped hazelnuts.
4. Divide the batter into 20 mounds on the prepared baking sheets, about 1/4 cup each. Bake until the outsides are dry and crispy, but the insides are set but still slightly soft, about 25 minutes. Alternate baking sheets about halfway through for even baking. Remove from oven and allow to cool on the baking sheet for 10 minutes. Remove to wire rack to cool completely. Can be stored on a platter with a light covering such as paper towel. This will keep them crispy.