Mussels with basil and lemon grass

Ingredients

• 1 kilogram large black mussels
• 2 teaspoons olive oil
• 1 (80g) small brown onion, chopped finely
• 2 cloves garlic, crushed
• 1 large stick fresh lemon grass (20g), sliced thinly
• 1 fresh long red chilli, chopped finely
• 1 cup (250ml) fish stock
• 2 tablespoons lime juice
• 2 tablespoons fish sauce
• 1/3 cup fresh thai basil leaves, loosely packed, finely shredded
• 1/2 cup (125ml) light coconut milk
• 2 green onions, sliced thinly
• lime juice, extra