1cup8 oz, or 2 sticks unsalted butter, at room temperature
1cupunsweetened cocoa powder, I used Dutched dark cocoa powder which worked well
1 ½cupsall purpose flour, fluff the flour before scooping and leveling the cup, too much flour will result in a dry dough
For the coating:
16ouncessemi-sweet baking chocolate
1tspvegetable or coconut oil
Approximately 1 teaspoon peppermint extract or oilMake sure you get peppermint, not spearmint, and make sure you get extract, or oil, not flavoring I used McCormick's Pure Peppermint Extract
Set the oven to 350F
Cream butter until light and fluffy, then add the powdered sugar and mix until combined. Stir in the salt, vanilla and cocoa powder. Mix until the cocoa powder is integrated and the batter resembles a thick frosting. Add the flour and mix just until the flour is combined, making sure to not over mix.
Form dough into a ball. Knead a few times to bring together, then flatten into a disk between half an inch and one inch thick, cover in plastic wrap then place in freezer for 15 minutes.
Remove dough from the freezer and roll it out really thin on a floured surface, about 1/8-inch. Cut cookies using 1 1/2-inch cutter (I used a small cordial glass that measured almost 2" and it was the perfect size).
Place cookies on a baking sheet and bake for 10 minutes. Remove the cookies from the oven and allow them to cool completely on a wire rack. While the cookies bake, make the peppermint coating. Chop the baking chocolate into very small, thin pieces. Place in a glass measuring cup or similar container along with the oil and microwave in short 15-20 second bursts. Stir in the peppermint extract. Feel free to add more peppermint as you see fit. (Don't add any more, the amount is perfect)
Gently drop the cookies, one at a time, into the coating. Turn to coat entirely, then lift the cookie out of the chocolate with the fork and bang the fork on the side of the pan until the extra coating drips off. Place on a parchment or plastic wrap-lined baking sheet, and repeat for the rest of the cookies. Place the cookies in the refrigerator or freezer to set. (I didn't need to do this, they set up fine after about 1/2 hour at room temperature, but then again, we were having a blizzard, "room temperature" is relative!)
Be sure that your butter is truly at room temperature before you start. If your butter is cool the dough will not come together well.
Use the 'fluff and scoop' method to measure out your flour. That means fluff up the flour in the canister or bag to loosen it BEFORE you scoop or spoon out your measurement. Level the top of the measuring cup gently with the back of a knife to get the most accurate measurement. This goes without saying, but use a measuring cup meant for dry solids, not liquids for measuring flour.
Some people are having trouble adding the peppermint extract to the melted chocolate. I have updated the recipe to add a bit of vegetable oil to the chocolate, this should help. You can also try putting the extract right in with the chocolate before melting. Remember everything must be clean and dry, with no moisture in the bowl, and you must use an oil based flavoring, so definitely read the labels on your peppermint extract. Candy flavoring oils are also a good choice. I used McCormick's Pure Peppermint Extract. If you can't find it in your grocery store you can buy it from Amazon, HERE.
https://theviewfromgreatisland.com/homemade-thin-mints/ March 3, 2012