lightly adapted from: Epicurious.com, originally from Gourmet 2006
3/4 cup hazelnuts
6oz good bittersweet chocolate, finely chopped (or same weight bittersweet chocolate chips)
2 3/4 c. AP flour
2 tablespoons cocoa powder
2 t baking powder
3/4 t salt
1 stick butter, at room temp
1 1/2 c sugar (the recipe calls for brown but I used mostly granulated b/c I ran out...)
1/4 c whole milk
1 t vanilla
3/4 c powdered sugar
Roast hazelnuts on an ungreased baking sheet or cake pan at 350 for 10 minutes, or until they start to brown and the skins loosen. Dump into the center of a kitchen towel, fold the edges over the nuts, and let cool for five minutes, then rub briskly in the towel to remove skins. (It's fine if some stubborn skins stay on.) [Turn oven off.] When they're cool, whirr in a food processor until finely ground.
Melt chocolate. As it cools...
Stir together flour, cocoa, baking powder and salt.
Cream together butter and sugar until, well, creamy. Beat in eggs, then milk, then vanilla, then chocolate. Stir in dry ingredients, then ground nuts. Cover and chill 2+ hours.
Preheat oven to 350 and put one rack in the top part of the oven and one in the bottom. Line two cookie sheets with parchment paper. Take half of the dough out of the fridge and sift powdered sugar into a small bowl. Shape dough by hand into about 1.5 inch diameter balls (meatball-sized), then roll in powdered sugar. I shook them gently to loosen some of the powdered sugar and thought it was plenty, but if you want stark white sugar on your cookies in the end pile it on thick. I didn't flatten my doughballs at all and ended up with mound-cookies, which were fabulous, but if you want thinner ones, flatten them slightly.
Bake for 15-18 minutes, swapping position of the cookies sheets (top to bottom and bottom to top) about 8 minutes in. I'm not sure at what point in this business they crack, but trust me, they will. When they're done a toothpick stuck into a crack should come out mostly clean and the edges should feel firm and dry (tap them with the toothpick to check). If you have a cooling rack big enough, slide the whole parchment sheet+cookies onto the rack all at once. (I wish I could take credit for that stroke of brilliance, but, alas, I can't.) Don't forget about the other half of the dough in the fridge; it is waiting to be rolled once you finish the first half. Let the sheet cool and then re-paper and continue baking cookies until the dough is gone. I ended up with 32 cookies. Eat while still warm and soft in the center with a glass of milk, a cup of coffee, or a glass of red wine.