Heat 1 tablespoon of butter in a pan and cook the shallots, garlic, leeks and bay leaf for 10 minutes, taking care not to burn. Add a little plenty of salt and pepper.
Turn up the heat, add the wine and let it boil for 2 minutes. Add the mussels and boil, stirring frequently, until they begin to open. They are taken out on a plate. Those that do not open are thrown away.
The sauce in which the mussels were boiled is mixed with the rest of the butter and fresh creams, using a whisk. Add the mussels back to the pan, along with the lemon juice and peel and the parsley.
Serve immediately with the wand.