Sweet onion vinaigrette with roasted garlic

You know those salad dressings at restaurants that make every bite addicting, but you can't quite put your finger on why? This sweet onion vinaigrette is one of those dressings.

So what's the secret to a good sweet onion vinaigrette? Roasting the onions.

While onions add depth to nearly every recipe, their sharp bite can easily dominate the flavor of a salad dressing. Roasting creates a salad dressing that's both more mellow and more complex at the same time.

With just 5 minutes of prep time, your dressing will be ready after it's done roasting and you blend it up. It's surprisingly light on calories too!

Jump to:

• How to make a good vinaigrette that doesn't break
• Are sweet onions actually sweet?
• Tips for roasting
• Store in the fridge or freezer
• Best salads & other uses
• Recipe
• More sweet onion dressing recipes

How to make a good vinaigrette that doesn't break

In an ideal world, your vinaigrette ends up the perfect consistency.

I like to err on the safe side and start with a slightly thicker dressing than I can slowly thin down. It's much harder to thicken it back up.

Both honey and mustard are emulsifiers, but mustard is far superior and shouldn't be left out or substituted.

The type of mustard matters

Believe it or not, the type of mustard makes a big difference. Mustard is your main emulsifier - it's job in a vinaigrette is to bind oil and water together.

The outer coating of mustard seeds contain mucilage, the main stabilizer that keeps dressings from breaking.

Dijon and whole grain mustards both contain a good amount of the mustard seed shells, which is why they're better emulsifiers than plain yellow mustard.

How to thin the dressing

You have several options for thinning your sweet onion dressing. Add your thinning liquid slowly, since it's much harder to thicken it back up.

• Olive oil: a thinner consistency while preserving a rich texture (think adding heavy cream vs water to soup)
• Apple cider vinegar: use cautiously so you don't add too much acidity
• Apple juice: sweetens and thins it out
• Water: thins out the dressing, no extra calories

How to thicken the dressing

It's harder to thicken a vinaigrette, but still doable.

• Add an emulsifier: Dijon mustard, honey, egg yolks
• Add more roasted onions and garlic, if you still have some around

If you want to learn more about the science behind a basic vinaigrette, check out this recipe on Serious Eats.

Are sweet onions actually sweet?

"Sweet onions" is kind of a false name.

They aren't actually sweeter than regular onions, even when sugar levels are measured. However, they have about a third of the sulfurous compound that gives onions their characteristic bite.

Since sweet onions have a milder flavor, they are well suited for a salad dressing.

Vidalia, Walla Walla, and Maui onions

Sweet onions are a category, whereas Vidalia, Walla Walla, and Maui are branded names of sweet onions.

• Vidalia are grown in Georgia
• Walla Walla are from Washington
• Maui are from Hawaii

I haven't tasted a noticeable difference in flavor between the brands, and buy whatever is available (or on sale!).

Tips for roasting

The onions and garlic typically roast in about 45 minutes. I have a few tips to make sure you have a tasty sweet onion dressing by the time you are done.

Charred onions are delicious

Cut the onions into quarters so they roast faster, but try to leave the quarter intact.

The quartered onions should soften, caramelize, and get charred on the edges. All of this creates desirable flavors.

If you separate the onion layers before roasting, they won't develop the caramelized flavors before the edges burn.

You might want to roast a whole head of garlic

You only need 4 cloves of garlic for this sweet onion dressing, but you could just roast an entire head of garlic to save for other recipes this week.

Roasted garlic is sweeter and more mellow than fresh garlic. That's why it's so good in so many recipes:

• Add to mashed potatoes
• Mix in with butter for garlic bread
• Use in soups, like this roasted garlic potato soup

Store in the fridge or freezer

This sweet onion dressing lasts for a week in the fridge, so you can use it on salads all week or make it ahead of time.

Double the recipe and freeze leftovers. You can portion it out into ice cube trays for individual portions.

Best salads & other uses

This kale and lentil salad with sausage is probably my favorite use for a Vidalia onion vinaigrette. It clings to the kale, coats the lentils, and pairs perfectly with the sausage.

This dressing is also excellent on sandwiches, specially Italian subs, ham and cheese, and grilled chicken.

I occasionally make this sweet onion dressing into a thicker sauce for dipping. It works great with chicken strips, veggie trays, and onion rings.

Recipe

More sweet onion dressing recipes

If you're looking for other sweet onion dressings, here are a few other options worth considering:

• The Herbeevore has a very similar version, but without the roasting
• Better Food Guru has a red onion dressing sweetened with maple syrup
• Southern Living has a version with added poppy seeds (and no roasting)

Other salad and dressing recipes to try

Since I focus on using fresh fruits and vegetables, I make a lot of salads. Here are a few to try: