Preheat the oven to 180ºC fan oven/200ºC/gas 6. Grease or line a couple of baking trays.
Cream together the butter and sugar.
Add the Nutella, vanilla and the egg and beat well.
Add the flour, cocoa, chocolate chips and the pecans. Mix well.
Put dessertspoons of the mixture well apart on the trays. They will spread quite a lot and make quite thin cookies.
Bake for 12 minutes in the oven. They will look as though they are not cooked, but when left to cool, will be crunchy on the outside and chewy in the centre.
Once cooled, drizzle with a bit of melted white chocolate.
