In New Zealand, kumara is an age-old crop which remains a firm favourite - with good reason.
Maori have grown kumara extensively since bringing it to New Zealand over 1000 years ago. They showed great skill cultivating and storing kumara, and managed to control the potentially devastating kumara caterpillar by using tamed black-backed seagulls. The original kumara were very small but in the early 1850s, a larger American variety was quickly adopted for its superior size and flavour. The majority of kumara are grown in Northland where the soil and climate are ideal. In other countries, kumara is known as sweet potato.
New Zealand kumara are available in red, gold and orange varieties. They each have a different skin and flesh colour, texture and flavour. Red kumara, with red skin, has a creamy white flesh with a firm texture and mellow flavour. The gold-skinned kumara has golden flesh with a soft texture and it is sweeter than red kumara. Orange kumara has orange skin and flesh, a firm texture and the sweetest taste.
Kumara will retain their flavour and freshness for a week or two after purchase if you keep them in a cool, dark, well ventilated place. Don't store them in the fridge and keep them out of warmer temperatures to avoid sprouting. As with potatoes, if you peel the skin and throw it away, you're throwing away some of the goodness (fibre, vitamins and minerals), so just give kumara a good scrub and trim any bruising or woody bits. Kumara can be used as an alternative in any recipe that uses potatoes. You'll find they generally cook a little quicker than potatoes.
More sweet potatoe(kumara) recipe ideas here: http://allrecipes.com/recipes/1094/fruits-and-vegetables/vegetables/sweet-potato/