准备

• In a medium bowl, whisk together the butter and granulated sugar until well combined. Whisk in the vanilla and chocolate. Add the egg and whisk until thoroughly incorporated.

  In another medium bowl, stir together the flour, cocoa powder, salt, and baking soda until well mixed. Using a wooden spoon, stir the flour mixture into the chocolate mixture. The dough will start to seem too floury, and you will find it easiest to switch to mixing it with your hands until it comes together. It will have the consistency of Play-Doh. Let the dough sit at room temperature for about 1 hour to firm up.

  将面团转移到15英寸正方形的羊皮纸或蜡纸上。用双手将面团形成约10英寸长，直径为2-1/2英寸的粗糙原木。将日志放在羊皮纸纸的边缘，然后将羊皮纸滚动在日志上。将日志完全包裹在羊皮纸中，将其卷成更平滑的日志，将其保持直径为2-1/2英寸。冷藏至少2小时，或直到牢固。该日志可能会沉降并在冰箱中沉降一点，因此，如果您愿意，每15分钟左右重新卷一次以保持圆形日志。如果没有，您的饼干将比圆形更长方形，这不是一件坏事，尽管它们看起来不像著名的包装饼干。（在这一点上，面团原木可以用塑料包裹很好地包裹，并在冰箱中储存长达1周或在冰箱中持续1个月。如果面团被冷冻，请在冰箱中融化过夜，然后再进行冰箱。）

  Position a rack in the center of the oven, and heat the oven to 325°F. Line a baking sheet with parchment paper or butter it.

  Cut the dough log into 1/4-inch-thick slices. Place the slices about 1 inch apart on the prepared baking sheet.

  烘烤20至25分钟，或直到饼干牢固地触摸为止。16或17分钟后经常检查它们，将它们戳在中间。一旦他们感到坚定，就将其从烤箱中取出。您无法通过颜色判断，因为它们开始黑色。在电线架上的烤盘上冷却以加热或室温。他们不必在填充它们之前完全冷却，但是在它们很热的时候您无法填充它们。

  While the cookies are cooling, make the frosting. Using a stand mixer fitted with the paddle attachment (or a handheld mixer), beat the butter on low speed for about 30 seconds, or until completely smooth and soft. Add the confectioners’ sugar and vanilla and beat until the mixture is perfectly smooth. Add the milk and salt and again beat until smooth. It will look like white spackle and feel about the same—like putty. You can also mix this frosting by hand. Make sure the butter is very soft, and use your hands to mix and knead the confectioners’ sugar into the butter. You should have about 1 cup. (The filling can be stored in an airtight container at room temperature for up to 2 days or in the refrigerator for up to 2 weeks. Bring to room temperature before using.)

  将大约1大汤匙填充物sc到1个饼干的底部。顶部是第二个饼干，底部向下，然后将饼干压在一起，将填充物朝边缘铺设。重复直到填充所有饼干。