For the spaghetti with arugula pesto and nuts, cut the arugula and put it in a tall narrow container.
Roughly chop the garlic and add to the arugula together with the salt, oil and grated nuts.
Blend with a hand blender until creamy, add a little more water if necessary, mix in the cheese.
Cook the spaghetti in enough salted water until al dente, strain and serve mixed with the pesto.
Sprinkle the chopped hazelnuts on top and serve the spaghetti with rocket pesto.