These cookies use Nutella and then incorporate both cocoa and hazelnut extract to accentuate the flavors of the Nutella. To customize the cookies for a holiday, roll the balls of dough in colored sanding sugar before you press them flat.
Whisk the flour, cocoa powder, baking powder and baking soda together in a mixing bowl.
Place the butter and sugars in a separate mixing bowl.
Beat them together at medium speed until the mixture is creamy, using either a stand mixer with a flat paddle attachment or an electric mixer.
Add the vanilla and hazelnut extracts to the butter mixture and beat them all together for an additional 30 seconds.
Add 1/2 of the dry ingredients to the wet ingredients and mix them on low speed until the dry ingredients are just incorporated.
Add the milk and beat the mixture until combined.
Pour in the rest of the dry ingredients and mix them until the batter is smooth.
Spoon in the Nutella and beat the mixture until all of the ingredients are incorporated.
If the dough does not pull together, add additional tablespoons of milk until the dough becomes thick and pasty.
Cover the mixing bowl with plastic wrap and chill the dough for 15 to 20 minutes in your refrigerator.
Preheat the oven to 325°F (160°C) and line a baking sheet with parchment paper.
Spread some flour on a plate.
Press your clean hands into the flour and dust them off so that a thin coating remains.
Take some dough with your hands and make a ball that is about 2″ (5 centimeters) wide.
Place the dough ball onto your baking sheet.
Continue flouring your hands and forming the dough into balls.
Leave about 2″ (5 centimeters) of space around each cookie on your baking sheet.
Dip the bottom of a drinking glass in the flour and press it into the top of a ball of dough to flatten it.
If the cookie sticks to the glass, then gently peel it off and place it on the baking sheet.
Continue flouring the glass and pressing it into the dough until all of the cookies are flattened.
Bake the cookies for 10 minutes.
Remove the pan from the oven and place it on the stovetop.
Allow the cookies to cool on the stovetop for 2 minutes.
Then, use a spatula to loosen them from the parchment paper and to move them to wire racks for cooling.