Unlike regular potatoes, sweet potatoes, which are full of vitamins, minerals and high in fibre, count as one of your five-a-day. Leave out the cheese in this one if you’re on a diet. Choi sum can be replaced by purple sprouting cabbage, spinach, asparagus or a mix of all of them. The ravioli can be made in larger quantities and frozen. They will need to be cooked from frozen, with an extra 2-3mins added to the cooking time.