Heat the olive oil in a saucepan, add the onion and fry until softened but not coloured. Add the garlic and fry for one minute.
Add the mussels and white wine, cover with a lid and cook over a high heat until the shells have opened. After 4-5 minutes, remove any broken shells or ones that have not opened and discard.
Add the cream and tomatoes and boil over a medium heat for 1-2 minutes. Add the chopped parsley and coriander and season, to taste, with freshly ground black pepper.
Spoon into two serving bowls and serve immediately.