Put the olive oil and butter/margarine into a good sized frying pan (with a lid) and then fry, not too quickly, the chopped garlic and shallots.

When the shallots and garlic are just transparent, (about two minutes), add the water, wine, bay leaf, parsley and mussels.

Add ground pepper to taste and pour cream over the mussels.

Cover pan with lid, over moderate to high heat.

When liquid starts to steam, keep over the heat, constantly shaking the pan until all (or at least most) of the shells open.

This will only take three, or four minutes.

Do not overcook and avoid letting the liquid boil.

You will hear the shells crack open and when most have opened, remove from heat.

Too much cooking will only make them tough.

Serve immediately (only the ones that opened) in bowls with plenty of sauce and crisp fresh bread.