SWEET ONIONS (Vidalia, Walla Walla, Maui, Texas Sweet): High sugar content imparts mild flavor. A good choice for raw use, such as in salads and sandwiches or in salsa, if you prefer low heat. Because of their high water content, sweet onions generally don't keep as long as others.
WHITE ONIONS: Glossy white appearance. One of the more pungent onions. Use raw on burgers, sandwiches, salsa and similar dishes if you like warm, but real tasty onions. Otherwise, they can be used in any recipe that calls for cooked onions.
YELLOW ONIONS: Golden color with relatively strong flavor. May be used cooked or raw, depending on your taste for a somewhat pungent onion. Long, slow sauteing at very low heat brings out sweet, mellow flavors.
RED ONIONS: Purple in color rather than true red, they are relatively mild. Appealing raw in salads or sauteed in stir fries. Also good for other cooking. Adding a bit of vinegar, wine or lemon juice helps keep color from fading or turning purplish-blue. You'll often find red onions in salads at restaurants.
SHALLOT: This is a small relative of the onion with dry, coppery skin. The flavor combines onions and garlic. Somewhat hot when raw, but it cooks to a delicate flavor.
SCALLIONS: This is a variety of onions that is harvested at an immature stage before the bulb has formed. Mild flavor. A green onion is not the same as a scallion, though the names are often interchanged. Green onions have tiny white bulbs at the bottom while scallions are younger and have straight white sides at the root end.
LEEKS: Another onion relative that's actually in the scallion family. A leek looks like a large, fat scallion with a white root and dark green, overlapping leaves. Mild flavor. Only the root is used. Careful trimming and cleaning are necessary because dirt accumulates in the leaves.
