Cook The Book: Chocolate Sablés

• 8 ounces semisweet chocolate, finely chopped
• 1 1/2 pound (2 sticks) unsalted butter, room temperature
• 1 cup sugar
• 1 large egg
• 1 teaspoon pure vanilla extract
• 1 cup cake flour, sifted then measured
• 1 cup potato starch flour
• 1/2 cup Dutch-processed cocoa powder
• Pinch of salt
• 1/2 cup crystal sugar, for decorating

1. In the top of a double boiler or in a bowl over simmering water, melt the chocolate. When chocolate is nearly melted, remove from heat and stir until smooth. Set aside to cool; return to double boiler only briefly if chocolate begins to set up.
2. In a mixer fitted with the paddle attachment, beat the butter at medium speed until smooth and pale. Add the sugar; continue beating, scraping down bowl sides often, until mixture is completely smooth, 3 to 5 minutes total. Beat in the egg and vanilla until blended.
3. Pour in melted chocolate; mix at medium-low speed just until blended, scraping down bowl sides several times.
4. In another bowl, with a fork, mix together the cake flour, potato flour, cocoa powder, and salt. Add to the chocolate mixture; mix at low speed until just blended. Try not to overmix.
5. Put the bowl of dough in refrigerator; chill for 10 to 20 minutesuntil firm enough to handle but not too stiff.
6. Transfer dough to a lightly floured surface. By hand, press dough into a log about 15 inches long and 2 1/2 inches in diameter. (If dough is too tacky, loosely wrap in sheet of plastic wrap to form roll.)
7. Spread the crystal sugar on a baking tray. Place the log (with plastic wrap removed) in sugar; roll to evely coat all surfaces except ends. Wrap well in plastic wrap; chill until firm, at least 4 hours or up to 3 days. Log can also be frozen.
8. Position 2 racks in middle of oven; preheat to 350u0b0F. Have ready 2 cookie sheets lined with parchment paper or Silpat nonstick baking mats. Remove dough from refrigerator; let sit for about 10 minutes, until warm enough to slice evenly. Using a thin-bladed chef's knife, cut log into 1/4-inch slices. Transfer slices to prepared cookie sheets, leaving 1-inch space between each.
9. Bake 10 to 12 minutes, until tops are dull. Cool on wire racks. Can be stored in airtight container up to one week.

chocolate, unsalted butter, sugar, egg, vanilla, cake flour, potato starch flour, dutch, salt, crystal sugar

Taken from www.seriouseats.com/recipes/2008/02/cook-the-book-chocolate-sables.html (may not work)