准备

做饼干：

• 将面粉和可可放入一个中等大小的碗中。用手动搅拌机或带有桨叶附件的立式搅拌机，以中等速度将黄油和糖奶油奶油，直到轻巧蓬松，约2分钟。加入香草和盐；继续跳动直至混合和光滑，再过大约1分钟。加入面粉咖啡酸混合物，以低速混合直至形成柔软的面团，约1分钟。将面团在冰箱中冷却，直到足够牢固地滚成40至60分钟的球。

  将架子放在烤箱的中心，然后将烤箱加热至350°F。在两个饼干板上排成两个饼干或不粘烤衬里。

  用手掌将面团的茶匙堆成1英寸的球。将它们排在两英寸的床单上。用轻轻的面粉拇指或成分指尖，直接向下压入每个球的中间，几乎几乎向曲奇纸做得很好。（或使用厚实的木勺的末端。）

  Bake one sheet at a time until the tops of the cookies look dry, 8 to 9 minutes. Gently redefine the indentations with the end of a wooden spoon. Let the cookies cool on the sheet for 5 minutes and then let them cool completely on racks.

进行填充：

• Put the chocolate and butter in a heatproof bowl set in a wide skillet of almost simmering water. Stir with a heatproof spatula until almost melted, 2 to 4 minutes. Remove the bowl from the heat and stir until melted and smooth, about 30 seconds more. Stir in the mint extract. Let the filling cool, stirring occasionally, until slightly thickened and a bit warmer than room temperature, 30 to 40 minutes. Spoon the filling into a small pastry bag with a small plain tip. (Or use a small plastic bag and cut a tiny bit off a bottom corner of the bag.) Pipe the filling into the center of each cookie. Cool completely before serving or storing. The cookies will keep in an airtight container at room temperature for 4 to 5 days.