If you can’t find blanched hazelnuts, simply toast and skin regular ones.
- ½ cup unsalted, roasted almonds
- ½ cup (packed) light brown sugar
- ½ vanilla bean, split lengthwise, or 1 teaspoon pure vanilla extract
- 1½ cups all-purpose flour
- 1 cup (2 sticks) chilled unsalted butter, cut into pieces
Preheat oven to 350°. Toast hazelnuts on a rimmed baking sheet, tossing occasionally, until golden brown, 8–10 minutes. Let cool.
Combine almonds, brown sugar, salt, and ½ cup hazelnuts in a food processor. Scrape in seeds from vanilla bean; reserve pod for another use. Pulse until finely ground, then pulse in flour just to combine. Add butter; process until dough just comes together.
Roll dough into 1” balls and place on parchment-lined baking sheets, spacing 2” apart. Flatten cookies to a little less than ½” thick. Coarsely chop remaining ½ cup hazelnuts and press gently into cookies.
Bake, rotating sheets halfway through, until cookies are golden brown, 15–18 minutes. Transfer baking sheets to wire racks and let cookies cool completely.
DO AHEAD: Cookies can be baked 5 days ahead. Store airtight at room temperature.