3/4 cup confectioners sugar", "3 tablespoons cocoa powder", "1/4 cup bittersweet chocolate, chopped", "1/8 teaspoon salt", "2 egg whites", "1/4 teaspoon cream of tartar", "1/8 teaspoon salt", "1/2 cup sugar", "1 teaspoon vanilla extract
Instructions
Place the whole hazelnuts and 1 tablespoon oil in a food processor and process until a smooth paste is formed, 4-5 minutes, scraping down sides if necessary.
Add confectioner's sugar, cocoa, chocolate, remaining tablespoon of oil and salt and process until smooth.
Transfer to a container and chill until mixture has hardened, at least 2 hours and up to 8.