Makes 2 dozen 3-in cookies
2 c. all-purpose flour
1/4 c. unsweetened cocoa powder
1/2 t. each baking soda and salt
1 stick unsalted butter, softened
1 1/2 c. sugar
1 c. Nutella
1 t. vanilla extract
Finely chopped hazelnuts (I used pecans)
Whisk together flour, cocoa powder, baking soda, and salt in a bowl; set aside.
Beat butter and sugar with a mixer on medium speed, 5 minutes. Add eggs one at a time, beating to fully incorporate before adding the next.
Add Nutella and vanilla; beat until combined. Add flour mixture; mix just until combined. Chill dough 4 hours or overnight.
Preheat oven to 350. Line baking sheets with parchment paper.
Scoop dough with a #30 scoop (scant 3 T.); roll in hazelnuts. Bake cookies, six at a time, until edges are set, about 15 minutes. Let cookies cool on baking sheets.