Preheat oven to 350 F. Line two baking sheets with parchment paper.
Whisk together ground nuts, flour and cocoa.
In a mixer beat butter and sugar on medium speed until light and fluffy. Add extracts and beat to blend.
Reduce speed of mixer to low and gradually add flour mixture until a dough forms.
Use a cookie scoop or a teaspoon to portion out dough. Roll it gently in your hands and place balls two inches apart on cookie sheets. Use the end of a wooden spoon to create a well in each dough ball. Do not go all the way down to to the cookie sheet.
Bake 1o minutes minutes.
Remove from oven and fill each well with Nutella (to come level with the top of the cookie). Return cookies to oven for 5 minutes more.
Remove to wire cooling racks and dust with Confectioners' sugar.