Wash the mussels thoroughly in two or three changes of cold water. Remove the beards from the mussels and discard any shells that are broken. Put them into a large saucepan with some white wine, a garlic clove and a little oil. Cover and cook over a medium heat for about four minutes or until the mussels have opened, shaking the pan a couple of times. Remove any mussels that haven’t opened.
Then, heat the olive oil in a frying pan with a garlic clove. Sauté until garlic is pale gold.
Now add the tomatoes, some parsley and cook on a low heat for about five minutes or until the tomatoes are soft. Then, add the strained mussel juice, increase heat and cook until reduced by half.
At this point, add the mussels and add salt to taste.
Cook spaghetti in plenty of lightly salted boiling water until al dente. Drain and toss with mussel sauce, adding a slug of olive oil and some salt and pepper.