Smoked salmon & lemon risotto

INGREDIENTS

• 1 onion , finely chopped
• 2 tbsp olive oil
• 350g risotto rice , such as Arborio
• 1 garlic clove , finely chopped
• 1½l boiling vegetable stock
• 170g pack smoked salmon , three-quarters chopped
• 85g mascarpone lite
• 3 tbsp flat-leaf parsley , chopped
• grated lemon zest , plus squeeze of juice
• handful rocket