First of all wash all the nettles in running water and pick over the leaves. Keep all good leaves and the tops of nettles whole, but discard old or tough stalks. Make sure you use gloves for this!
Chop the onion and garlic clove (if using) finely.
Add vegetable oil to a large saucepan and add the onion and garlic. Fry on medium heat for about 5 minutes or until the onion becomes see through.
Peel the potato and roughly chop to smaller pieces.
Add about 500 ml of boiling water to the saucepan and dissolve a cube of vegetable stock in.
Add the chopped potato and nettles and boil for 15 or 20 min, until the potatoes are soft (the smaller the potatoes are the faster they will be done)
Add half of the garlic leaves if using towards the end of the boiling time (you don't want the leaves to boil for too long)
Pour into a suitable container (or blender) and puree the soup using a hand held liquidiser (or blender).
Return back to the saucepan, taste, season and reheat.
Add a dash of cream and serve with few chopped wild garlic leaves. To add extra protein to the soup, you can add a boiled egg.