If you love Nutella (or other chocolate-hazelnut spreads), you'll want to bake up a big batch of these cookies; the recipe can easily be doubled or even tripled. No mixer is needed to make the dough, which calls for just five ingredients, all likely to be in your larder, and which can be made up to a few days ahead and kept, well covered, in the refrigerator. Then it's just a matter of rolling the dough into balls, flattening them a bit, and baking.