The milder flavor of sweet onions make them perfect for recipes that use a lot of onions, or where the onion flavor shouldn't be strong. They aren't actually sweeter than regular yellow or red onions, they just have less of the characteristic 'bite' that onions are known for.
French onion inspired
French onion soup is traditionally made with yellow onions, but sweet onions are gaining popularity. When caramelizing onions for any French onion type of recipe, cook until golden brown or dark golden brown - avoid cooking until they are very dark brown or black, which will add bitter notes.
Dips usually shouldn't taste very onion-forward, which is why sweet onions are often the best choice. Even when raw, their flavor is mild. To make it even milder (which probably isn't necessary), you could soak the cut onion slices in water for 10 minutes. The compounds that give onions their sharp flavor a water soluble, which is why soaking helps.
Soups & salads
Salads are another obvious choice for sweet onions, as their flavor won't take over the rest of the dish. Salad recipes that call for red onions can usually be substituted with sweet onions (or soak the red onions to remove their sharp flavor).
Soups, on the other hand, aren't always the best choice for sweet onions. Sometimes they are (as shown in the recipes here), where you want a light onion flavor that mixes well with the other ingredients. Other soups (especially heartier ones) benefit from the stronger flavor of yellow onions. Substituting sweet onions into some soup recipes might leave the broth tasting a bit flat.
Sweet onions and onion rings are a perfect match. But they are good for so much more - again, lending a subtler onion flavor that doesn't overpower the side dish.
Sweet onions have a higher water content and cook quickly. If you're looking for a quicker dinner, they could be a good option. They are also excellent when grilled.
Vidalia, Walla Walla, and Maui are the most widely available sweet onions and are all quite similar in flavor. Their seasons differ just slightly.
- Maui: Peak: April - August, but can be found year round
- Vidalia: April - August
- Walla Walla: June - September
- Texas Sweet: April - June
Sweet onions don't store as long as other types of onions, due to their higher water content and thinner skin. They will last only about a week on the counter, a month in a cool & dark place, or more than a month in the fridge.