Step 1

Heat the olive oil in a large saucepan over medium heat. Add the onions, garlic and chilli and cook for 3 minutes or until the onions have softened slightly.

Step 2

Increase heat to medium-high and add the tomatoes and stock and bring to the boil. Simmer, uncovered, for 20 minutes.

Step 3

Add the mussels. Cover and cook for 5 minutes or until the mussels have opened and are just cooked. Discard any unopened mussels.

Step 4

Add the basil and sugar. Taste and season with salt and pepper. Serve with crusty bread.