Place the sea salt & garlic into the food processor bowl & pulse briefly until they are combined. Pestle & mortar -grind the salt & garlic until you form a paste.
Pull all the leaves from the stems and add to the food processor. Gently pulse until the leaves have broken down and reduced in the bowl. Pestle & mortar - adding a few leaves at a time, gently grind into the garlic & salt mix.
Now begin to add the oil. Add about half to begin with, pulse and then check the consistency. Add more as required. If you are using the pestle & mortar, you can place the leaves, garlic and salt in a larger bowl and gently stir in the oil.
The pesto can be as smooth or chunky to suit your taste preference. If you need extra oil, add as required.
Now add the pepper & parmesan if you are using it. Taste and check for seasoning
Store for 3-5 days in a clean jam jar or Kilner jar. To sterilise the jar, wash in warm soapy water, then pop it into your oven at a 160-180 degrees for 15 minutes to kill any bacteria.