Rinse the mussels under running water, no sand should remain. Clean the beard, seaweed. Throw away broken or otherwise unreliable. Better not to risk it. In the recipes, it is written that each still needs to be fertilized and checked to see if it is alive. I skip this step, especially when I have to check a larger quantity. However, in no way do I ignore another piece of advice, to immediately throw away and not eat those that are produced and will not open.
Prepare other ingredients. Cut onions, garlic, leeks, celery, if you add hot pepper.
Prepare the tools you will need. A large pot where you will cook the mussels, a spatula for mixing. It's more fun to cook when everything is at hand.
Fry the onions and/or leeks in the same pot in which everything will be cooked, on butter or olive oil, whichever you prefer. When the onions are soft, add the garlic and pepper.
Reduce the heat and pour the wine into the pot. Wait until it heats up and the alcohol evaporates.
Add the celery and mussels, cover and let them cook in the wine for a few (3-4) minutes.
Check and if the clams have already opened, pour the cream. Wait a minute, another for the cream to heat up and remove from the heat.
Add parsley and then it's ready to serve!