Mussel soup

1 kilogram mussels
1 large carrot
1 onion
1/2 celery root
2 leeks
1 tbsp butter
1 bouillon cube
fresh parsley, salt and pepper

1. Thoroughly clean closed mussels under the cold tap. Discard broken and open shells. Put the other mussels into a pan and add 1.5 litres water. Cover the pan and boil contents until the shells open (about 10 minutes). Put the mussels onto a platter, strain the juice and discard any unopened shells.
2. Grate the carrot, peel and dice the celery root, peel the onion and slice into rings, rinse the leeks and slice into rings. Put the butter in a pan and sautT the vegetables for 15 minutes. Rinse the parsley and finely chop it. Add it to the vegetables with the juice and the stock cube. Pull the mussels from their shells and add to the soup. Season to taste.