Prepare the mussels by washing them in cold water and removing any beards. Discard any that are damaged.
In a large saucepan heat the olive oil and saute the sliced onion and garlic until soft. Do not allow the garlic to burn.
Add the white wine and corn flour and heat gently, stirring to thicken the mixture a little. Season to taste with a little salt.
Add the mussels to the saucepan and put a lid on. Allow the mussels to steam away in the saucepan for about 8 – 9 minutes or until all the shells have opened. Discard any mussels that have not opened.
Serve the mussels garnished with the chopped parsley, the sauce poured over and slices of wholemeal cob loaf to mop up the broth.
Notes
For the white wine, I just use a cheap Pinot Grigot. If it's just for cooking, there's no point in spending a lot on an expensive wine.