1. 1. Preheat the oven to 150°C (300°F). Line a baking sheet with parchment paper.

2. 2. In a food processor, grind the hazelnuts until coarsely chopped. Transfer to a bowl and set aside.

3. 3. In a large mixing bowl, beat the egg whites and granulated sugar until stiff peaks form.

4. 4. Gently fold the chopped hazelnuts into the egg white mixture until fully combined.

5. 5. Drop rounded tablespoonfuls of the mixture onto the prepared baking sheet, spacing them about 2.5 cm (1 inch) apart.

6. 6. Bake for 20 to 25 minutes, or until the edges turn golden brown.

7. 7. Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.

8. 8. Melt the dark chocolate using a double boiler or in the microwave in 30-second intervals, stirring between each, until smooth.

9. 9. Dip the top of each cooled cookie into the melted chocolate, then place them on parchment paper or a silicone mat.

10. 10. Refrigerate for at least 30 minutes to allow the chocolate to set.

11. 11. Enjoy your homemade crispy hazelnut cookies!