1. Turn the oven on to the temperature of 180 degrees.
2. Put about 14 to 16 muffin cases on an oven tray.
3. In a large bowl mix together all the dry ingredients: flour, sugar, baking powder, baking soda and chocolate chips. In another bowl mix well the milk with the eggs, the butter and the scoop of Nutella. Then add the wet mixture to the dry one and blend with a spoon until you get a lumpy batter.
4. Scoop the batter into the muffin cases and cook for about 15 to 20 minutes.
5. Take off the oven and allow to cool.
6. Apart prepare the chocolate icing, this is my way and it always work!
7. Put the chopped chocolate and the water into a bowl sitting over a pan of simmering water, allow to melt then take off the heat, let cool then add the icing sugar and stir carefully.
8. Spread the icing on the top of the muffins, then sprinkle the chopped hazelnuts on top of the icing and finally -- enjoy your creation!