1. Preheat oven to 225°C (425°F). Line a baking sheet with parchment paper.

2. In a large bowl, combine the finely ground hazelnuts and confectioners' sugar. Mix thoroughly.

3. In a separate bowl, beat the almond paste and egg whites until smooth and fully incorporated.

4. Gradually fold the nut and sugar mixture into the almond paste mixture until a thick, uniform batter forms.

5. Using a small spoon or piping bag, portion the mixture into small mounds (about 1 tablespoon each) onto the prepared baking sheet.

6. Press one whole hazelnut gently into the top of each mound.

7. Bake for 4 to 5 minutes, just until the edges are set and the surface dries—do not overbake. Remove and let cool completely.

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

9. Once the mounds are cool, dip the base of each one into the melted chocolate, swirl to coat about one-third, and scrape the bottom lightly against the bowl.

10. Place back on parchment and let the chocolate harden at room temperature or in the refrigerator for 10 minutes.

11. Store in an airtight container at room temperature for up to 1 week.