Choose firm, heavy-feeling sweet potatoes with skin that is even in color, with no bruising or soft spots.

The sweet potato should not have an unpleasant smell.

Look for ones that are not too bumpy: the shape doesn't affect the flavor, but they will be much easier to peel.

Avoid any with signs of rot. 

Sweet potatoes are not particularly fragile. They are easily handled and should be stored in a cool, dry, well-ventilated place to prevent sprouting.

Use sweet potatoes within two weeks of purchase. Bear in mind that they keep for a much shorter time than potatoes.

Do not refrigerate unless already cooked. Cold temperatures will cause a hard core and an off taste when cooked.

The skin is not usually eaten. Peeling them simply requires a peeler or paring knife and some elbow grease, since the skin is fairly hard and takes longer to peel than a potato.

For an easier method, wrap them in aluminum foil and bake in the oven. The peel can then be easily removed.

Cook them as soon as they are cut; the flesh oxidizes quickly once exposed to air. If you slice or cube them, put them immediately into water with a little lemon juice. Speaking of oxidiation, they don't like contact with metal objects, either.  

If you're considering baking them whole in the oven, just brush and rinse well before baking. 

BAKED
Prick the skin and bake at 200°C / 400°F until done for approximately 40-70 minutes. depending on their size. Peel, cut and use as desired.

STEAMED
In a steamer basket placed over boiling water, peeled sweet potatoes can be steamed, whole or cubed, in about 30-50 minutes.

BOILED
Peeled sweet potatoes can be cooked, whole or cubed, in boiling water for 30-50 minutes. As with potatoes, place the sweet potatoes into cold water before placing on the heat. Prick with a knife to check for doneness. They can then be blended into a delicious mash. 

SAUTÉED

MICROWAVED
Prick the skin and microwave on high power for four to six minutes for one medium sweet potato.

NOTE
Sweet potatoes contain no starch, therefore potatoes need to be added to bind sweet potato soup.

Mash with a fork with butter or cream and a good grinding of fresh pepper.

Purée in a blender with cream, brown sugar and ginger.

Boil, cut into matchsticks and serve in a vinaigrette with shrimp, grapefruit and arugula.

Boil peeled and quartered sweet potatoes in orange juice with salt, pepper, ginger and nutmeg. Thicken the cooking liquid with starch and add a spoonful of honey..

Pacific Islands

Caribbean and South America

Haiti

Madeira
French fried sweet potatoes are a true dessert: the natural sugars crystallize to make the fries crispy. Cook in the oven, cut into cubes and fry until the sides caramelize.

Japan
Sweet potato is relied on as a hearty winter food. Known as "satsuma imo," it is particularly valued in savory dishes, but it is also used in desserts: mashed with butter and sugar, it is formed into little balls, glazed with egg and baked. Served with matcha tea, this sweet is a common treat during the cold season. 

Morocco
Sliced and stewed with braising beef, seasoned with paprika, cayenne, turmeric, cumin, parsley and coriander.