Delicious, that's what they are.  I found the recipe on Deadspin, and
it's reproduced below.  I made two changes.  One, I left out the
hazelnuts (didn't have 'em in the house).  Two, I was baking for 13
minutes, because the first batch at 10 minutes was a little soft
coming out of the oven.

---

Nutella Cookies

2.5 cups flour
0.5 teaspoon baking powder
0.5 teaspoon baking soda
1 teaspoon salt
1 cup butter (softened)
1 cup packed dark brown sugar
1 cup granulated sugar
approx. 26 oz Nutella (one large jar)
1 cup chopped hazelnuts
2 large eggs
2 teaspoons vanilla extract

In one bowl, whisk together flour, baking powder, baking soda and
salt. Set aside.

In the bowl of a mixer, cream the butter and the two sugars until all
is integrated and fluffy. Mix in the Nutella, followed by the chopped
hazelnuts. Beat in the eggs one at a time, followed by the vanilla.

Add the flour mixture to the mixing bowl in three increments,
integrating each one before adding the next. Chill dough while oven
preheats to 350F. Scoop the dough into balls and bake for about 10
minutes.