This recpe requires few ingredients, is easy to follow and highly adaptable.
Simply by switching out some of the flour for cocoa powder, you can make the dough base a chocolate one.
The logs of dough need to be refrigerated overnight, and up to 1 week (The logs of dough can be frozen for up to 1 month).
The cookies can be stored in an airtight container at room temperature for up to 5 days.
18 tablespoons(2 1/4 sticks) chilled salted butter, cut into 1/2-inch pieces
1/2 cup granulated sugar
1/4 packed cup light brown sugar
1 teaspoon vanilla extract
2 cups plus 2 tablespoons all-purpose flour
1/4 cup plus 2 tablespoons cocoa powder, preferably Valrhona brand
170 g Ferrero Rocher candies, coarsely chopped (12 to 13 pieces; round up when in doubt)
Demerara sugar, for rolling
1 large egg, beaten
Flaky sea salt, for sprinkling
Line a rimmed baking sheet (or two, ideally) with parchment paper.
Combine the butter, both sugars and the vanilla extract in the bowl of a stand mixer or with a handheld electric mixer; beat on medium-high speed for 3 to 5 minutes, until the mixture is light and fluffy.
Stop to scrape down the sides of the bowl.
Add the flour and cocoa powder; beat on low speed until incorporated, then add the chopped Ferrero Rocher candies (they'll be a little messy, it's okay), and beat just to incorporate.
Divide the dough in half, placing each half on a large piece of plastic wrap or parchment paper.
Use the plastic or paper (to protect your hands from stickiness) to roll and shape each portion of dough into a log, wrapping it at the same time.
Each log should be 2 to 2 1/4 inches in diameter. Refrigerate until totally firm, about 2 hours, and up to 1 week.
Preheat the oven to 350 degrees.
Spread the Demerara sugar on a piece of plastic wrap. Unwrap the logs; brush their exteriors with the beaten egg, and then roll the logs in that sugar.
Discard any sugar that's left behind.
Slice each log into 1/2-inch-thick rounds, placing them on the prepared baking sheet(s) about 1 inch apart, and sprinkle with flaky salt.
Bake (middle rack) for 12 to 15 minutes, until the edges are just beginning to brown.
Let cool slightly before serving, or cool completely before storing.
Based on an Alison Roman recipe; adapted by cookbook author and food writer Charlotte Druckman.