- 1 cup chocolate-hazelnut spread
- 1/3 cup white sugar
- 2 tablespoons water
- 2/3 cup heavy whipping cream
- 1/4 teaspoon coarse sea salt (such as Diamond Crystal®)
- 1/2 cup unsweetened cocoa powder
- 1 (12 ounce) bag chocolate chips (at least 60% cocoa), finely chopped
- 1 tablespoon coarse sea salt (such as Diamond Crystal®), or to taste
- Heat hazelnut spread in metal bowl over saucepan of gently simmering water and stir until hazelnut spread is warm, smooth, and easily stirred, about 5 minutes. Remove bowl from heat.
- Dissolve sugar in water in a small saucepan over medium heat. Brush sides of pan with a moistened pastry brush occasionally as sugar mixture cooks. Increase heat to medium-high and bring syrup to a boil and cook until syrup is a deep amber color, brushing down sides and swirling saucepan occasionally to prevent scorching, about 4 minutes.
- Pour cream into the syrup while stirring. Reduce heat to low and cook, stirring continually, until you have a smooth caramel, 5 to 10 minutes; gently stir into the melted hazelnut spread with 1/4 teaspoon sea salt.
- Refrigerate caramel mixture until firm, at least 3 hours.
- Spread cocoa powder into the bottom of a wide, shallow bowl.
- Scoop caramel mixture with a melon baller into 1 tablespoon portions; roll in the cocoa powder to coat; arrange onto a baking sheet.
- Cover truffle balls with plastic wrap and chill overnight or 8 hours.
- Line a 13x9x2-inch baking sheet with aluminum foil.
- Heat chopped chocolate in a metal bowl set over a saucepan of gently simmering water, stirring frequently until chocolate is melted and smooth and the chocolate reaches a temperature of 115 degrees F (46 degrees c). Remove bowl from over water.
- Working quickly, submerge each truffle ball in the melted chocolate. Lift truffles from chocolate with a fork and tap fork against side of bowl to remove excess coating. Transfer truffle to foil-lined pan to cool. Repeat with remaining truffle balls.
- Sprinkle finished truffles lightly with 1 tablespoon coarse sea salt before the chocolate hardens. Let stand until coating sets completely, at least 1 hour.