Mix the butter with the sugar until frothy. Add the eggs and vanilla extract and stir until smooth. Mix the flour with the baking powder and stir half into the mixture. Then mix in the other half. Stir in the chocolate chips.
Spread the dough tablespoon at a time on a baking sheet lined with baking paper. Make a small hollow in the middle with a teaspoon and fill it with some Nutella. Then put some batter on the cookies and close the well with your fingers.
Bake on the middle rack for about 15 minutes. ATTENTION: the cookies don`t really get dark, so don`t let the color fool you.
Tip: Instead of chocolate chips you can also use three crumbled biscuits or something similar.