Just as other fruits grow scarce, tamarillos arrive to perk up wintry cakes and desserts, chutneys and salsas. Available from late autumn, they hit their peak in July and August. They are good sources of vitamins A, B6 and C, vitamin E and thiamine and are high in potassium. To store, refrigerate them for up to two weeks. They will keep in your fruit bowl for about one week. Tamarillos can easily be frozen – either whole or pureed.