If you love French onion soup and roasted garlic, this one is for you. This Roasted Garlic and Caramelized Onion Soup is rich, creamy, and packed with slow-cooked onion and garlic flavor.
The onions cook low and slow in butter until they’re deep golden and sweet, while three whole bulbs of garlic roast until soft enough to squeeze right out of the skins. Blend everything together with chicken stock, Parmesan, and a little heavy cream and you get a nice comforting bowl of soup.
And if you really want to take it over the top, serve it with a crispy grilled cheese for dipping. That combination is Off the Chain!
Why You’ll Love This Recipe
- Loaded with flavor – Three bulbs of roasted garlic and slowly caramelized onions give this soup a ton of flavor.
- Rich and creamy – Heavy cream and freshly grated Parmigiano Reggiano make it extra smooth.
- Perfect comfort food – This is the kind of soup you want when the weather starts cooling down.
- Great with grilled cheese – Make a grilled cheese on the side and start dipping.
- Easy to make ahead – The soup reheats really well, so you can make it ahead for an easy lunch or dinner.
What You’ll Need
Garlic – You’re using three whole bulbs. Roasting mellows out the sharp garlic flavor and makes it sweet, soft, and almost buttery.
Onions – Four large onions may look like a lot at first, but they cook way down as they caramelize.
Butter & Olive Oil – Using both gives the onions plenty of flavor while helping them cook evenly.
Sugar – Just a teaspoon helps bring out the onions’ natural sweetness as they caramelize.
Flour – A tablespoon of all-purpose flour slightly thickens the soup.
White Wine – Adds another layer of flavor and helps lift all those browned bits from the bottom of the pot.
Chicken Stock – The base of the soup.
Heavy Cream – Gives the finished soup that creamy texture without making it too heavy.
Parmigiano Reggiano – Freshly grated Parmesan melts right into the soup and adds salty, nutty flavor.
Parmesan Rind – Totally optional, but if you have one sitting around, throw it in while the soup simmers. It adds even more Parmesan flavor.
Thyme – Dried thyme works perfectly here.
Salt & Pepper – Season as you go and adjust at the end.
How to Make Roasted Garlic and Caramelized Onion Soup
1. Roast the Garlic
Preheat your oven to 400°F.
Slice the tops off all three bulbs of garlic so the tops of the cloves are exposed. Drizzle with a little olive oil, wrap each bulb in foil, and roast for about 40–45 minutes, or until the cloves are soft and golden.
Once they’re cool enough to handle, squeeze the roasted garlic cloves from the skins and set them aside.
2. Caramelize the Onions
While the garlic is roasting, add the butter and olive oil to a large Dutch oven over medium-low heat.
Add your sliced onions along with a pinch of salt and the sugar.
Cook for about 30–40 minutes, stirring often, until the onions are soft, deeply golden, and caramelized.
Don’t rush this part. The slower the onions cook, the better the flavor.
Set aside a small amount of the caramelized onions to use as a topping later.
3. Deglaze the Pot
Pour in the white wine and scrape the bottom of the Dutch oven to loosen all those browned bits.
Add a small splash of chicken stock if needed and let everything cook for another minute or two.
Those browned bits are flavor, so make sure you get them up from the bottom of the pot.
4. Build the Soup
Sprinkle in the flour and stir it into the onions.
Add the roasted garlic, remaining chicken stock, dried thyme, and Parmesan rind if you’re using one.
Bring everything to a gentle simmer and cook for about 10–15 minutes.
5. Blend Until Smooth
Remove the Parmesan rind.
Use an immersion blender to blend everything directly in the Dutch oven until the soup is smooth and creamy.
Taste and season with salt and black pepper.
6. Finish With Cream & Parmesan
Reduce the heat to low and stir in the heavy cream and freshly grated Parmigiano Reggiano.
Let the cheese melt into the soup, then taste one more time and adjust the seasoning if needed.
Ladle into bowls and top with some of the caramelized onions you set aside earlier and a little extra Parmesan.
Tips for the Best Roasted Garlic and Caramelized Onion Soup
Don’t rush the onions. Caramelizing onions takes time. You want them golden brown and sweet, not just softened.
Roast the garlic until completely soft. You should be able to squeeze the cloves right out of the bulb.
Use freshly grated Parmesan. Parmigiano Reggiano melts better and gives you much better flavor than pre-shredded Parmesan.
Save those Parmesan rinds. Instead of throwing them away, keep them in the freezer for soups and sauces like this one.
Serve it with grilled cheese. Trust me on this one. Dunking a crispy grilled cheese into this soup might be the best part.
FAQs
What if I don’t have an immersion blender?
If you don’t have an immersion blender thats ok. Just allow soup to slightly cool and transfer into a large blender. Blend until smooth and return to your pot.
How long does roasted garlic and caramelized onion soup last?
Stored in an airtight container in the refrigerator, the soup should keep for about 3–4 days.
Can I freeze it?
You can, although cream-based soups can sometimes separate slightly after freezing. For the best results, freeze the soup before adding the heavy cream and Parmesan, then add those ingredients after reheating.
Do I have to use white wine?
No. You can use only chicken stock if you don’t want to use wine. You’ll still get plenty of flavor from the roasted garlic and caramelized onions.
What should I serve with it?
A grilled cheese is hard to beat. You could also serve it with crusty bread, garlic bread, or a sandwich.
What kind of onions should I use?
Yellow onions are a great choice because they become sweet and flavorful as they caramelize. Sweet onions will also work.
Roasted Garlic & Carmelized Onion Soup
Ingredients
- 3 whole bulbs garlic
- 4 large onions sliced
- 3 tablespoons butter
- 1 tablespoon olive oil plus a little extra for roasting garlic
- 1 teaspoon sugar
- 1 tsp Dried thyme
- 1 tablespoon all-purpose flour
- ⅓ cup white wine
- 4 cups chicken stock
- ⅓ cup heavy cream
- ½ cup freshly grated Parmigiano Reggiano
- 1 leftover Parmesan rind optional
- Salt and black pepper to taste
Instructions
- Preheat oven to 400°F.
- Slice the tops from the garlic bulbs, drizzle with a little olive oil, wrap in foil, and roast for 40–45 minutes, until soft.
- Add butter and olive oil to a large Dutch oven over medium-low heat.
- Add sliced onions, sugar, and a pinch of salt.
- Cook for 30–40 minutes, stirring often, until deeply caramelized.
- Remove a small amount of the onions and reserve for topping.
- Add the white wine and scrape up the browned bits from the bottom of the pot. Add a splash of chicken stock if needed.
- Stir in the flour.
- Squeeze the roasted garlic cloves into the pot.
- Add the remaining chicken stock, dried thyme, and Parmesan rind.
- Simmer for 10–15 minutes.
- Remove the Parmesan rind and blend the soup until smooth using an immersion blender.
- Season with salt and black pepper to taste.
- Reduce heat to low and stir in the heavy cream and grated Parmigiano Reggiano.
- Serve topped with reserved caramelized onions and additional Parmesan if desired.
