Waxy Fingerling and New Potatoes

• Many purple and blue potatoes in U.S. supermarkets are small 1- to 2-inch round "new potatoes," which is a generic term for any type of potato harvested before it reaches maturity. Produce distributors frequently package them in new-potato trios that also contain red- and white-skinned spuds. Purple fingerling varieties are available in some supermarkets and most natural food stores. Both types typically are very small, although some oblong fingerlings may be longer than 3 inches. New potatoes and fingerlings are waxy, low-starch spuds, which means they yield denser, stick-to-your-ribs mashed potatoes.

Purple Waxy Potato Varieties

• Purple Peruvian fingerling potatoes are small, elongated spuds with dark-purple skin and flesh. They yield a deep lavender or purple mash. Adirondack blue potatoes have brownish-purple skin and purple flesh that yield lavender mashed potatoes. Any small, round purple potato that is about 1-inch long or labeled a new potato -- such as the blue potatoes in red, white and blue trios -- likely has the qualities of waxy spuds regardless of the characteristics true to their varieties when mature.

All-Purpose Potatoes

• Larger purple and blue potatoes -- about 3 to 5 inches long -- typically are all-purpose potatoes, which have moderate levels of starch. This is the same category of potatoes to which familiar Yukon golds belong, so you may expect their textures and consistencies to be similar. All-purpose potatoes are less firm and easier to mash than waxy spuds, so they yield fluffier mashes than new potatoes and fingerlings.

Purple All-Purpose Potato Varieties

• Purple majesty potatoes have dark-purple skin and flesh that yield a purple mash. They also have a buttery flavor, which is perfect for mashed potatoes. All blue potatoes have dark-purple skin and purple-and-white-marbled flesh that becomes paler when you cook them, yielding a soft lavender-hued mash. Royal blues, purple Vikings and caribes have purple skin and white or yellow flesh. They yield white mashes that contain streaks of purple if you leave the skins intact.

Cooking Methods That Preserve Color

• Steaming or microwaving purple-fleshed potatoes preserves the colors of the skin and flesh more effectively than boiling them. The flesh often becomes less vibrant and grayer regardless of the cooking method, which is why some potatoes with deep-purple flesh yield lavender mashes. Steam potatoes whole or cut into chunks until they are fork tender. Microwave potatoes in a dish or bowl tightly covered with plastic wrap until they are tender, approximately 10 minutes. Cut a vent in the plastic so steam can escape.

Mashing Purple Potatoes

• Prepare purple mashed potatoes as you would white or yellow potatoes. Keep in mind that cream, milk, cream cheese, sour cream and any other creamy, opaque dairy ingredients may lighten the color of the finished mash if you used purple-fleshed spuds; dairy will not alter the color of purple skins in the mash.