Preheat the oven to 170°C. Roast the hazelnuts for 10-12 minutes, then let them cool.

Rub the hazelnuts between your hands to remove the skins. Set aside 25 whole hazelnuts and chop the rest.

Heat the cream in a saucepan over medium heat until it just starts to simmer.

Remove from the heat, add the chopped dark chocolate, and stir until smooth and fully melted.

Stir in the hazelnut paste until smooth and fully combined. Set aside.

Melt the chocolate, then stir in the chopped hazelnuts.

Prepare a dome-shaped silicone mold with cavities 2-3 cm in diameter. Fill each cavity halfway with the warm ganache, then place a whole hazelnut or half a hazelnut in the center. Freeze for at least 15 minutes.

Unmold the frozen ganache and press two half-spheres together to form a 2-3 cm ball. Roll and press each one in the chopped roasted hazelnuts. Insert a toothpick into each ball, then chill or freeze.

If you don't have a dome-shaped silicone mold, scoop out 1 tablespoon of cooled ganache and flatten it slightly in your palm. Place a whole hazelnut in the center, then wrap the ganache around it to form a 2-3 cm ball. Insert a toothpick into each ball, then chill or freeze.

Hold each ball by the toothpick, then dip the chilled chocolate balls into the chocolate-hazelnut coating. Let the excess chocolate drip off for a few seconds, then refrigerate.

Wrap each chocolate in an 8.5 x 8.5 cm square of gold or silver foil, then place it in a small gold truffle cup.