Delicious Italian hazelnut shortbread cookies sandwiched with rich dark chocolate!
- Preheat oven to 350˚F/175˚C then toast hazelnuts on a baking sheet until they are fragrant and golden, about 5-8 minutes. Turn the oven off for now.
- Place hazelnuts into a kitchen towel and gather up ends then shake and rub the hazelnuts around in the towel to remove their skins.
- Place the hazelnuts into the bowl of a food processor and discard the skins.
- Add the sugar to the food processor and pulse until the nuts and sugar reach a sandy texture, about 30-60 seconds.
- Add the flour, cornstarch and salt and pulse to combine.
- Add the butter in small cubes and the vanilla extract then process everything together to form the cookie dough.
- Wrap the dough in parchment paper and chill for 30 minutes.
- Form the dough into roughly 60 small balls, about 1 level teaspoon of dough per ball.
- Freeze them on a baking tray for 30 minutes. Once they are frozen they can be transferred to a freezer bag and stored in the freezer until ready to bake if you are making the dough ahead of time.
- Preheat the oven to 300˚F/150˚C while the dough balls are in the freezer. Line 2 half-sheet pans with parchment paper.
- Arrange the dough balls spaced out to fit 30 per baking sheet.
- Bake for 12-15 minutes, switching the trays halfway through, until the cookies are domed and golden.
- Let the cookies cool on the pans for a few minutes then transfer them to cooling racks and allow them to cool to room temperature before proceeding.
- Chop the chocolate into small pieces.
- In a heat-safe bowl set over a saucepan of simmering water or in a double-boiler, melt about 3/4 of the chocolate then remove the bowl from the heat and stir in the remaining chocolate until it melts.
- Let the chocolate cool for about 10-15 minutes so it starts to set up. It is easier to sandwich the chocolate when it is just starting to set up, otherwise, it is too runny.
- Match up similarly sized pairs of cookies. Working quickly because the melted chocolate will set up fast, sandwich a small spoonful of melted chocolate between the pairs of cookies.
- Let the chocolate set completely then transfer the cookies to a lidded storage container. Enjoy within 1 week.