Chocolate Nutella Cookies

1 1/2 cups all-purpose flour, lightly spooned into measuring cups and leveled with a knife
1 teaspoon baking powder
1/2 teaspoon salt (omit if using salted butter)
2/3 cup Dutch-process unsweetened cocoa powder
1/2 cup (1 stick) butter
1/2 cup sugar
1/2 cup dark brown sugar
1 1/2 teaspoons vanilla
1/2 teaspoon hazelnut extract (you can substitute 1/2 teaspoon vanilla if you can’t find or don’t like hazelnut extract)
1/3 cup Nutella
1/3 cup milk

In a small mixing bowl, whisk together the flour, cocoa powder, and baking powder. Set the mixture aside. In a large bowl, beat together the butter, granulated sugar, and brown sugar with an electric mixer on medium speed for about 2 minutes or until smooth. Add the extracts and beat for another 30 seconds or so. Add the Nutella and beat until smooth.
With the mixer running, add half of the flour mixture and mix until combined. Add the milk, mixing until combined completely, then add the remaining flour mixture and mix completely. Cover and refrigerate the dough for at least 15 minutes (and as long as 2-3 days).
When you’re ready to bake the cookies, preheat the oven to 325 degrees and line a baking sheet with parchment paper. Roll tablespoons of dough into balls and place them on the lined cookie sheet, allowing about 2″ between the dough balls.
Lightly press the dough balls with the bottom of a drinking glass and then bake for 10-12 minutes or until the cookies are crackly on top and soft, but starting to set. Remove from the oven and allow them to stand for about 5 minutes and then transfer the cookies to a cooling rack and allow them to cool completely. Makes about 3 dozen cookies.

Source: http://www.ourbestbites.com/2011/08/chocolate-nutella-cookies/