Caramelized Onion Roasted Garlic Bisque is a warm and comforting silky soup that’s full of flavor, but not loaded with fat or calories.
This Onion and Garlic Soup Recipe is one of our favorite soups around my house. It’s warm and comforting, especially on those cold winter nights.
I first published this recipe in 2015, but have decided it was time for it to be updated with new photos, including photos of the steps to making this, and new information for a better user experience.
This recipe also made it as our #1 most popular recipe of 2022! Take a look at all the best recipes of 2022.
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Please let me know if you have any questions about this recipe. I read all the comments myself and I try to help as soon as I can. I have readers from all levels of comfort and experience in the kitchen on my site, and I’ve tried to answer some of your questions already in the post. But if I’ve missed anything, please feel free to leave a comment and ask.
Rich and creamy soup
It may take a while to make this comfort food soup, but it’s so worth it!
It’s a fairly simple recipe that doesn’t require much active working time, but uses fresh regular ingredients that you probably have in your kitchen all the time.
And, this soup is fairly light on calories for the flavor punch that it packs. It’s full flavored, just delicious, with all those onions and roasted garlic and leeks.
Simply, bisque means soup.
Don’t let the French word “bisque” scare you off; it’s just a fancy word for thick creamy soup made of puréed vegetables.
Classically, a bisque was a smooth cream soup based on crustaceans like lobster, langoustine, crab, shrimp, or crayfish.
Today, the definition of bisque has expanded to include thoroughly blended velvety vegetable bisques, and is more about the smooth texture of the dish and the use of cream.
So, is there a difference between bisque and soup? A bisque is a kind of soup. Which means that all bisques are soup, but not all soups are bisques. Hopefully that makes sense.
How to make this recipe
The printable recipe card with full instructions and ingredient amounts is below. Be sure to scroll down to grab it!
Roast the garlic
Remove the papery outer skin from the garlic head, but don’t peel or separate the cloves.
Rub ½ tablespoon of oil on the head of garlic, and wrap it in foil. Bake for 1 hour. Let the head of garlic cool before peeling it.
Separate the garlic cloves and peel the skin off, and set the meat of the garlic aside.
Pro tip from reader Mary suggested that she roasts large batches of garlic and freezes them in zip lock bags. I love this idea! It would make quick work of this recipe when you’re ready to cook.
Caramelize onions and leeks
Prep the onion and leek by slicing the onion into thin pieces.
How to prep the leek
For the leek, cut the dark green part (the part you aren’t going to use) and the root end off of the leek.
The tasty parts of the leeks are the white and about 1 to 2 inches of the light green parts. The dark green part is very tough, and not really good to eat. Save the dark green part of the leek to add to homemade broth or stock. It adds a nice color and flavor.
Then cut down the leek lengthwise. Now you will see that there are layers. Rinse the muddy dirty part that’s between the layers out.
Heat 1 tablespoon oil in a large saucepan over medium to low heat. Add the chopped onion and leek, and cook 30 minutes, stirring often.
When you caramelize veggies, it brings out so many flavors. Nutty, roasted, complex flavors.
Add ½ teaspoon salt and thyme, and cook an additional 30 minutes or until onion is dark and golden in color, stirring occasionally, adding a small amount of water if the onion starts to cook too fast.
Be careful not to burn the onions. Keep an eye on them as they cook. Don’t go off and check Facebook or anything.
And, if the onions are cooking too fast, or starting to burn on the bottom, simply add a bit of water to the pan. About 2 tablespoons to ¼ cup or so. Stir that in, and it’ll slow down the cooking so the onions can caramelize rather than burn.
And don’t forget, the darker you cook the onions, the darker the soup will be, so don’t skimp on the caramelizing step.
Reader Mary also suggests that you can make large batches of caramelized onions in the crock pot and freeze in smaller baggies. Another great time saving tip!
Yes, definitely, it can be made with yellow onions, which are typically less expensive and more readily available.
I wouldn’t use red onions or white onions in this recipe though, they will change the color and the flavor too much.
Make the soup
Stir the flour into the onion mixture and cook for a minute. Add wine and broth, and bring to a boil. Reduce heat, and simmer 30 minutes.
Place the roasted garlic in the bowl of a blender, add the remaining ½ teaspoon salt and cooked onion mixture, and process until smooth. This may need to be done in two batches depending on the size of your blender.
You could also add the roasted garlic to the pot and blend with an immersion blender.
I feel like the immersion blender doesn’t get things quite as smooth as the stand blender, but it is a nice time saver. You could also pour the mixture through a food mill.
Pour the blended onion mixture back to the large saucepan, and add the milk; simmer until thoroughly heated.
Garnish with fresh thyme leaves and ground black pepper if desired.
If you’re family doesn’t drink wine, you may not have any around.
In that case, I like to use more vegetable broth (or chicken broth if that’s what you used to make the soup) for this recipe.
What kind of milk should I use?
Feel free to use whatever milk you prefer, from whole dairy milk to lower fat dairy to vegan plant-based milks.
For the soup in the original pictures I used whole milk, but I’ll often use 1% milk.
The color of the soup will be darker if you use a lighter-fat milk.
I think refrigerated carton almond or cashew milk would be good plant-based milks to use in this for their neutral flavor.
Kitchen tools you may need for this recipe
Note: these are affiliate links
- Aluminum foil
- Immersion blender
- Soup bowls
- You could also use a food mill to get perfectly smooth soup
Hop over and pin it too! While you’re there check out all the people who have tried this caramelised onion soup and loved it!
What goes with garlic soup?
This is a really nice filling soup, so it doesn’t need much to make it a whole meal.
It’s a great way to start off a holiday dinner, like Christmas or Thanksgiving.
Serve this delicious soup with some freshly baked no knead bread.
You could even make cheesy croutons for topping the soup, kind of like a creamy French onion soup.
Sprinkle some Parmesan over the top when serving if you want.
Do you like garlic?
Here are some other garlic recipes you will love!
How to use leftovers?
This soup makes a nice big pot full, so I often find that we have leftovers.
I’ve used the leftovers as a sauce for pasta, adding in some toasted pine nuts and corn. Try adding some steamed broccoli and shredded chicken as well.
I’ve used the sauce as gravy over mashed potatoes or chicken.
You’ll love how delicious and versatile this creamy roasted garlic soup is.
Looking for other great comfort food? Try my Vegetarian Pot Pie. You’ll love it!
Can I freeze this?
Yes, this soup freezes really well. Allow the soup to cool completely, and place it in smaller freezer proof containers. Cover the container with an air-tight lid, and place in the freezer.
Store the soup for about 3 months. Longer than that, and it may start to pick up odors and flavors from the freezer.
Other great soup recipes
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Caramelized Onion Roasted Garlic Bisque
- 1 large whole garlic head
- 1 ½ tablespoons olive oil divided use
- 9 cups about 4 large thinly sliced sweet onions
- 2 ½ cups about 2 medium sliced leeks light green and white parts only
- 1 teaspoon salt divided use
- 1 teaspoon dried thyme
- 2 tablespoons all-purpose flour
- 1/3 cup dry white wine
- 4 cups vegetable broth
- 2 cups milk
- Fresh thyme leaves for garnish
- Freshly ground black pepper for garnish
- Preheat oven to 350° F.
- Remove papery outer skin from the garlic head (do not peel or separate the cloves). Rub ½ tablespoon oil on garlic head, and wrap it in foil. Bake for 1 hour; let cool 10 minutes. Separate cloves, and peel the skin off of the cloves. Place the garlic cloves in a small dish and set aside.1 large whole garlic head, 1 ½ tablespoons olive oil
- While the garlic roasts, heat remaining 1 tablespoon oil in a large pot over medium heat. Add onion and leek, and cook uncovered 30 minutes, stirring often. Add ½ teaspoon salt and thyme. Cook an additional 30 minutes, uncovered, or until onion is dark and golden in color, stirring occasionally, adding a small amount of water if the onion starts to cook too fast, and scraping up any brown bits off the bottom of the pot.1 ½ tablespoons olive oil, 9 cups about 4 large thinly sliced sweet onions, 2 ½ cups about 2 medium sliced leeks, 1 teaspoon salt, 1 teaspoon dried thyme
- Stir the flour into the onion mixture and cook 1 minute. Add wine and broth, and bring to a boil. Reduce heat, and simmer 30 minutes.2 tablespoons all-purpose flour, 1/3 cup dry white wine, 4 cups vegetable broth
- Place the roasted garlic in the bowl of a blender, add the remaining ½ teaspoon salt and cooked onion mixture, and process until smooth. This may need to be done in two batches depending on the size of your blender.
- Pour the blended onion mixture back to the large saucepan, and add milk; simmer 8 minutes or until thoroughly heated. Garnish with fresh thyme leaves and ground black pepper if desired.2 cups milk, Fresh thyme leaves for garnish, Freshly ground black pepper for garnish
Nutritional information is based on third-party calculations, and should be considered estimates. Actual nutritional content will vary based on brands used, measuring methods, portion sizes, and more.