Method

Pre-heat the oven to 200ºC fan.

Clean the mussels under running water, removing any beards.
Throw away any that stay open when tapped.
Place the prepared mussels in a large wide, dry saucepan, cover and cook over a low heat -
(there's no need to add any liquid but a splurge of dry white wine wouldn't go amiss)
- until they all open - takes just a few minutes.
Remove and discard the empty half shells and throw away any mussels that haven't opened.
Arrange the remaining mussels in their half shells in heatproof dishes.
Next, in a basin, combine the butter, garlic, lemon juice and parsley, season with salt and pepper and mix well.
Place a small dab of the savoury butter on each mussel then put the dishes on the top shelf of the oven and cook for 5-10 minutes or until the mussels are sizzling noisily.
Serve immediately, still sizzling and bubbling.