So, I've been trying to get this right since I found the recipe before Christmas. This is now my third try, and though the chocolate coating still needs massive improvement, the cookie part is nearly perfect! As my sister will tell you, words cannot describe how happy I was when I got the cookie part right. I may or may not have done a little victory dance in our kitchen... Also, this makes roughly 5 dozen cookies, give or take, so be prepared. That may sound like a lot, but in our house, they didn't even last 12 hours. Now THAT'S impressive. And it might be why our housemates are convinced that my co-baker and I are plotting to fatten them up for some evil fate.

Ingredients:
1 cup and 3 tablespoons butter, softened
1/2 cup white sugar
2/3 cup brown sugar
1 egg
1 3/4 teaspoon peppermint OIL! (Oil might be painful to find, but it's much better than extract, quality-wise. You can use extract in a pinch, but definitely up the amount used).
2 teaspoons vanilla
1 3/4 cup All-purpose flour
1/3 cup and 1 tablespoon cocoa powder
1/2 teaspoon baking soda
1/4 teaspoon salt
----
In a large bowl, cream together butter, then the sugars, then the egg. Add in the extracts, and blend for two minutes (or more).
Sift all remaining ingredients into a medium bowl, and add gradually to the wet mixture. Blend until incorporated, scraping sides with a spatula as necessary.
Freeze dough in several (about three) large balls. This is because the dough warms up and becomes gooey very rapidly, so keep whatever you're not working with in the freezer. Your
hands will thank you.
Preheat oven to 350*.
Once dough is hardened (about an hour), take out a block at a time, and roll small, 1-inch balls on to greased cookie sheets. Place the blobs about three inches apart.
With a cup dipped in cocoa powder, flatten the balls until they're about 1/4 inch thick. Bake 15-20 minutes, until the tops look dry and the cookies are firm; turn once during baking. Let cookies cool completely.
Now this next part needs work. I won't put up my proportions because 1) I don't know them precisely and 2) my version fails, and the cookies need to be frozen to not instantly melt everywhere. Oops... The trick is to get the mixture thin enough to dip well, but thick enough to harden. Chocolate only occasionally submits to my demands, and this was not one of those times, sadly.
But here's what you'll need:
Chocolate chips (probably not semi-sweet, 'cause that's what I used, and it wasn't sweet enough. Of course, at this point, you're probably well aware of my absurd sweet-tooth, but still, be warned)
Butter/Crisco
Heavy Cream
Peppermint Oil
----
Heat the cream and butter/crisco in a double boiler. Gradually add the chocolate chips, and a small amount of the peppermint. Using a fork and wooden spoon, dip the cookies and cover completely. Set on aluminum foil to cool, then move to fridge/freezer for complete setting. Beautiful:

Noms! Happy baking.
~The Baker's Apprentice/Chef A
EDIT: The chocolate coating actually did eventually set such that they don't have to be in the freezer constantly, but I still have no idea what the proportions are. Sorry!