In a large mixing, add the flour and sugars. Whisk to combine.
Now melt the dark chocolate in the microwave in 20 second intervals, stirring after each interval. Until melted. Add to the dry mixture.
Then add the salt, vanilla and vegetable oil. Using a hand mixer, beat together until fully combined.
Now stir in the chocolate chips and hazelnuts. Chill for about 10 minutes and serve! Yup just eat it with a spoon! It's awesome!
Notes
You can make this ahead of time, but if it is left in the fridge for hours it will get really firm. So you can just take it out of the fridge a while before you plan to eat it.