Clean the mussels by removing the beards and scraping any dirt carefully with a small Knives. Make sure that you discard mussels that remain open.
In a deep pot (one that has a lid), fry the chopped onion in the olive oil over a medium heat until they begin to soften.
Slice the streaky bacon thinly and add to the onion. Fry until the bacon starts to brown.
The garlic can be thinly sliced, or minced using a hand held crusher, and add to the pot and fry for a minute.
Add the mussels, and stir it around the pot, then add the shot of brandy. Place the lid on the pot and turn the heat up to high and cook for 3 minutes. Give the pot a little shake each minute to help the mussels release their juices, and help them open.
After 3 minutes all of the mussels should have opened, if not, close the lid and give it 1 more minute on a high heat.
Turn the hob off and add the single cream to the pot and stir in the chopped parley.
Serve immediately with some nice crusty bread. Discard any mussels that did not open during the cooking process.