1. Butter an 8-inch square straight-sided metal baking pan, then line it with parchment paper, allowing a 2-inch overhang on all sides.

2. Place the 4 tablespoons (2 ounces) butter, condensed milk, chocolate, chocolate-hazelnut spread, and kosher salt in a heatproof bowl set over (not touching) gently simmering water in a saucepan. Heat, stirring often, until the chocolate is fully melted and the mixture is well blended and smooth. Remove from the heat.

3. Using a rubber spatula, fold ¾ cup of the hazelnuts and the espresso powder into the chocolate mixture until evenly distributed.

4. Spoon the chocolate mixture into the prepared pan and, using an offset spatula, smooth the top or make a little wave pattern. Sprinkle the top evenly with a little sea salt and then with the remaining 2 tablespoons hazelnuts. Refrigerate for about 2 hours, until firm.

5. Using the parchment-paper overhang, lift the fudge out of the pan and place on a cutting board. Using a sharp knife, cut into about 36 (1¼-inch) squares.

6. Transfer each square to a confectionary cup, arrange the cups in an airtight container, and store in the refrigerator for up to 3 weeks. Let sit at room temperature for about 15 minutes before serving.

Reprinted from Holiday Cookies: Showstopping Recipes to Sweeten the Season by Elisabet der Nederlanden, copyright © 2017 by Ten Speed Press. Photographs copyright © 2017 by Erin Scott. Published by Ten Speed Press, an imprint of Penguin Random House LLC.