Another classic sweet onion is the Vidalia onion which has a flattened globular shape and light-yellow, almost white skin. Vidalia onions have a firm white juicy flesh with thin rings. When it comes to choosing a mildly tasting sweet onion, Vidalia onions usually hit the top of the list. These versatile onions are not only great for eating raw. You can increase their sweetness by lightly frying them, roasting them, or grilling them. They also make a delicious ingredient for any recipe that requires onions.