Prepare the mussels by washing them in cold water and removing any beards. Discard any that are damaged. Omit this step and step 2 if you are using pre-cooked mussels.
Bring 250ml water to the boil in a large pan. Add the mussels, place a lid on and allow the mussels to steam away in the saucepan for about 8 – 9 minutes or until all the shells have opened. Remove the mussels from their shells, set aside and discard any mussels that have not opened.