Firstly prepare the nettles to destroy the stinging hairs. Wash the nettles well. Bring a large pan of water to the boil and then drop in the nettles and blanch for two minutes. Rinse under cold water and then squeeze all the excess water out of them (at this stage we usually drink the cooking liquid as nettle tea, with a drop of honey to sweeten it).

Place the nettles in a blender with the parmesan, garlic, lemon juice, salt and pine nuts and blitz to a paste. Now with the motor still running drizzle in 125ml olive oil and continue to blend until the ingredients are thoroughly combined. Pour into a clean glass jar and top with the remaining oil; if stored in the fridge the pesto will last 2 weeks. Serve with fresh pasta, or drizzle over fish or warm salads.