- In a saucepan over medium heat, bring the cream and salt just to a boil. Remove the pan from the heat, add the chocolate and whisk until smooth. Pour the mixture into a bowl and let cool to room temperature, then cover and refrigerate until firm, 2 to 3 hours.
- Meanwhile, preheat an oven to 350°F.
- Put the hazelnuts on a baking sheet and toast in the oven until dark golden brown, 10 to 15 minutes. Let cool completely, then finely chop and place in a shallow bowl.
- Place the cocoa in another shallow bowl. Working quickly, roll a rounded measuring teaspoon of the chocolate mixture into a 1-inch ball in your hands, then roll in the hazelnuts, pressing them lightly into the truffle, lightly coat with the cocoa and set on a tray. Repeat with the remaining truffle mixture, hazelnuts and cocoa.
- Store between layers of waxed paper in an airtight container in the refrigerator until ready to serve, up to 1 week. Let the truffles stand at room temperature for about 15 minutes before serving. Makes 5 dozen truffles.
- TIP:This is a very flexible recipe. Use any nut you'd like instead of hazelnuts or coat the truffles with something else entirely—large clear sugar crystals, finely crushed graham crackers or crushed hard peppermint candies would all be terrific. Or just use the cocoa without nuts. Add a tablespoon or so of your favorite liqueur to the chocolate ganache, or use Cognac or other brandy or rum. If it pleases you, add instant espresso powder or replace some of the cream with mascarpone.
- You could also add minced dried tart cherries, a pinch of cinnamon or nutmeg, finely chopped fresh lemon or orange zest, or minced crystallized ginger. You can even steep Earl Gray tea, spices such as saffron or cardamom, or herbs (try rosemary or lemon verbena) in the cream to flavor it; strain and reheat gently before adding the chocolate.