- 2 cups (heaping) hazelnuts, preferably skinned (about 10 ounces)
- 1/4 cup sugar
- 1 pound semisweet or bittersweet chocolate, coarsely chopped
- 1/2 cup (1 stick) unsalted butter, cut into 1″ pieces, room temperature
- 1 cup heavy cream
- 3/4 teaspoon kosher salt
- Special equipment:Four clean 8-ounce jars
- Preheat oven to 350°F. Spread out nuts on a rimmed baking sheet or in an ovenproof skillet. Roast, shaking sheet once for even toasting, until deep brown, 13-15 minutes. Let cool completely. (If nuts have skins, rub them in a kitchen towel to remove.)
- Grind hazelnuts and sugar in a food processor until a fairly smooth, buttery paste forms, about 1 minute.
- Place chocolate in a medium metal bowl. Set bowl over a large saucepan of simmering water; stir often until chocolate is melted and smooth. Remove bowl from over saucepan; add butter and whisk until completely incorporated. Whisk in cream and salt, then hazelnut paste.
- Pour gianduja into jars, dividing equally. Let cool. (Gianduja will thicken and become soft and peanut butter- like as it cools.) Screw on lids. DO AHEAD: Gianduja can be made up to 4 weeks ahead; keep chilled. Let stand at room temperature for 4 hours to soften. Can stand at room temperature up to 4 days.