1 stick (4 ounces) unsalted butter softened
2/3 cup granulated sugar
3 large eggs, at room temperature
½ cup Nutella spread at room temperature
2 tsp vanilla extract
2 ¾ cups unbleached-all purpose flour
½ teaspoon baking powder
¼ teaspoon salt
1 cup chopped skinned toasted hazelnuts
5 ounces good-quality semi-sweet or bittersweet chocolate, cut into ¼ inch chunks, or 1 cup mini chocolate chips
- Preheat oven to 350 degrees.
- Place the butter and granulated sugar in the bowl of the stand mixer and beat on medium speed until smooth and slightly lightened in color, 2 to 3 minutes.
- Add the Nutella spread and blend well.
- Add the eggs, one at a time, beating well (15-20 seconds) and scraping down the sides of the bowl after each addition.
- Add the vanilla extract and mix well.
- In another bowl, whisk together the flour, baking powder, and salt. Add to the butter mixture and mix well.
- Add the hazelnuts and chocolate chips or chunks, and mix on low just until blended.
- Remove the bowl from the mixer and stir gently a few times with the spatula to make sure the nuts and chips are evenly distributed and there are no patches of unincorporated flour or butter.
- Divide the dough in half. On a work surface lightly dusted with flour, gently squeeze and roll each piece to shape into logs about 13 inches long.
- Line one baking sheet with parchment paper. Place the logs on the sheet about 4 inches apart.
- Press down on the logs, flattening them slightly until they are each about 2 inches across the top.
- Place the second baking sheet under the first (to prevent the bottoms of the logs from browning too quickly).
- Bake for 30 to 45 minutes, until the logs are firm to the touch and lightly golden brown.
- Transfer the pan to a cooling rack and let the logs cool completely. (If you attempt to slice them while warm, the chocolate will smear the cookies and look messy).
- Turn the oven down to 275 degrees and position two racks in the top and bottom thirds of the oven.
- Carefully transfer the cookie logs to a cutting surface. Using a serrated knife, slice the logs on a slight diagonal into cookies 3/8 inch thick.
- Line the second baking sheet with parchment paper. Place the cookies, cut side down, on the parchment-lined sheets (you’ll need both sheets to hold all the cookies).
- Toast the cookies in the oven, 30 to 40 minutes, until dry and lightly tinged with color. Transfer to a cooling rack.
- Wait longer than you think necessary to cut them. Just because the exterior is cool does not mean the inside is.
- Approximately two/three pieces on either end will crumble when you cut them. But don't worry the middle is much sturdier and will cut just fine.
- When you bake them the second time, take them out based on gut instinct, not a precise time. I waited and waited for the time to pass, and lost a few because they were burnt.