* Use real butter or stick margarine. Do not substitute reduced-fat spreads;
their higher water content often yields less-satisfactory results.
Sift the flour, cocoa, cinnamon and salt together and keep close at hand. Place
the butter in a mixer fitted with the paddle and beat on medium speed to soften
it. Gradually add the sugar and vanilla extract and continue to beat, scraping down
the sides of the bowl as needed, until the mixture is smooth and creamy but not
Reduce the mixer speed to low and add the flour mixture, blending only until
the ingredients are just combined - no more. Alternatively, you can remove the bowl
from the mixer and stir the flour into the dough with a rubber spatula. The point
is to mix the dough as gently as possible - this light touch is what will give the
cookies their characteristic crumbly texture.
As soon as the last of the flour is no longer visible, divide the dough in half,
shape each half into a ball, wrap the balls in plastic and chill for 30 minutes.
Working on a smooth surface, form each piece of dough into a log that's about
1 1/2 inches thick and 7 1/2 inches long. To get a solid log, one without that commonly
found hole in the center; use the heel of your hand to gently flatten the dough,
then flatten the dough lightly each time you fold it over on itself to make the
log. Assured that the log is solid, you can roll it gently under your palms to smooth
Wrap the logs in plastic and chill for 1 to 2 hours. (The dough can be made ahead,
wrapped airtight, and stored in the freezer for up to 1 month.)
Position the racks to divide the oven into thirds and preheat the oven to 350
degrees F. Line 2 baking sheets with parchment paper and set them aside.
In a small bowl, whisk the egg yolk until it is smooth and liquid enough to use
as a glaze; keep it close at hand. Spread some sugar out on a piece of wax paper.
Remove the logs of dough from the refrigerator; unwrap them and brush them very
lightly with a small amount of the egg yolk. Roll the logs in the sugar, pressing
gently on the sugar to get it to stick if necessary. Then, using a sharp slender
knife, slice each log into cookies 1/2 inch thick.
Arrange the cookies on the baking sheets, leaving about an inch of space between
each one, and bake for 15 to 18 minutes, rotating the pans front to back and top
to bottom at the midway mark, until the cookies are just firm to the touch.
the cookies to racks to cool to room temperature.
Unbaked logs of dough can be frozen for up to one month (before rolling them
Baked cookies can be stored in an airtight container at room temperature for
3 to 5 days.
Makes about 30 cookies.
Source: Chocolate Desserts by Pierre Herme and Dorie Greenspan