Preheat oven to 350°F (175°C).

Line baking sheets with parchment paper or use a nonstick cookie sheet.

In a large bowl, mix together the butter, Nutella, and egg until smooth.

Add the flour and stir until a dough forms and is well combined.

Using a cookie or ice cream scoop, portion dough onto the prepared baking sheet.

Lightly flatten each cookie using a fork.

Bake for 6–8 minutes, or until the edges are set and centers are still soft.

Let cool slightly before serving. Best enjoyed warm!