1. Preheat your oven to 170c degrees. Place your hazelnuts on a baking tray and put the tray in it the oven. Roast your nuts for about 15 minutes until you can see the skins coming away. Remove the hazelnuts from oven and allow to cool for 10 mins. Place your nuts in a clean tea towel and rub them until the skins are removed. I suggest doing this over a sink as it can be messy.
2. Put a pot of water on to boil and salt the water. Fill a large bowl with cold water and ice. When the water has boiled start to add a small batch of your basil leaves and allow to blanch in the water for a couple of seconds. Then remove with a slotted spoon and immediately put your blanched basil into your iced water, swishing about. When all the basil is blanched remove from the iced water and place on kitchen paper to get rid of the excess water. The blanching is an important step as it ensures your Pesto remains a vibrant green colour.
3. Chop your Parmesan into small cubes. Put all of your ingredients into a blender except your Salt and Pepper and blend until it reaches the right consistency for you. I personally prefer it to have a bit of bite. Remove the Pesto from the blender with a spatula and store in a clean jar. The Pesto keeps best in the fridge and can be kept for 1 week.