Finely chop the onion, garlic and celery. Heat the oil in saucepan and gently cook them until soft.
Rub the dirt off the skin of the potatoes (no need to peel them) then cut them into bite-sized chunks if too big. Cut the carrots in half lengthwise.
Add the potatoes and carrots to the onion, cook for 5 minutes.
Pour in the hot stock and cook for 10-15 minutes.
Slice cabbage leaves into thin strips, rinse them under water then add to the soup together with the green peas.
Cook the soup for a further 5-10 minutes. When the potatoes and carrots are tender, turn off the heat and add the mint leaves.
Season to taste with salt and pepper.
Serve with a spoonful of pesto if you like.