Try using golden caster sugar for a hint of caramel sweetness and warmer colour, or swap the lemon and lime for pink grapefruit for a fruity twist.
A shallow rectangular plastic lidded container is perfect for freezing the granita, but you can use any freezer-proof dish, such as a baking dish or tray and cover with clingfilm as needed. A shallow dish will help the granita freeze quicker, too.
In order to enjoy optimum flavour and quality, frozen items are best used within 3 months of their freezing date. For more tips on freezing and defrosting food, read our article Love Your Freezer.