01 -
Get your oven warming up to 350°F (175°C) and line two baking sheets with parchment paper.
02 -
Break out your electric mixer and cream together that softened butter and sugar until it's light and fluffy. Then mix in the vanilla extract until everything's well combined.
03 -
In a separate bowl, whisk together your flour, cocoa powder, and salt until they're evenly mixed.
04 -
Gradually add your dry ingredients to the butter mixture, mixing until you've got a firm, pliable dough that holds together nicely.
05 -
Roll the dough into 1-inch balls, then give them a good roll in those chopped hazelnuts. Place them on your prepared baking sheets, leaving about 2 inches of space between each cookie.
06 -
Make a little well in the center of each cookie with your thumb or a small spoon. Pop them in the oven for 12-14 minutes - you want them set but not hard.
07 -
While they're still warm from the oven, deepen those indentations if needed, then fill each one with a teaspoon of that chocolate hazelnut spread. If you're feeling fancy, top each with a whole hazelnut.
08 -
Let them rest on the baking sheets for about 5 minutes, then transfer to a wire rack to cool completely.