Whip the butter, sugar, and vanilla for 2 minutes. Add the flour, mix with a wooden spoon until fully mixed and not sticky anymore.
Shape the dough into 1 inch diameter balls. Place on a non-greased baking tray 2 inches apart. With your thumb or a measuring spoon make a print into the cookie.
Bake for 10-12 minutes or until the edges are light golden in color.
Fill your piping bag or a Ziplock bag (cut in the edge) with nutella.
After the cookies have slightly cooled fill with nutella.