Soak the peas in water for two days, changing the water once. They start to germinate easily.
On the day of preparation, clean the carrots, celery and leek and cut into small pieces. Finely chop the onions and sauté in a large saucepan in a little butter until translucent. Add the vegetables dripping wet and sauté. Season with salt and cardamom.
Drain the water from the peas. Add the peas and vegetable stock to the saucepan and simmer for about two hours until the peas are soft. Season to taste with pepper, salt and cardamom.
Serve in deep plates. Sprinkle some chopped, flat-leaf parsley over the top.