Roasted Garlic Onion Soup (Printable)

A comforting blend of slow-roasted garlic, caramelized onions and crispy herb croutons in a warm soup.

# What You Need:

→ Vegetables

01 - 3 large yellow onions, thinly sliced
02 - 2 whole heads garlic
03 - 1 large leek, white and light green parts, sliced
04 - 1 celery stalk, diced
05 - 1 medium carrot, diced

→ Fats

06 - 2 tablespoons olive oil
07 - 2 tablespoons unsalted butter

→ Liquids

08 - 1/2 cup dry white wine
09 - 5 cups vegetable broth
10 - 1 teaspoon soy sauce, optional

→ Herbs and Seasonings

11 - 2 sprigs fresh thyme
12 - 1 bay leaf
13 - 1/2 teaspoon dried oregano
14 - Salt and black pepper to taste

→ Herb Croutons

15 - 3 cups day-old baguette, cut into 3/4-inch cubes
16 - 2 tablespoons olive oil
17 - 1 tablespoon fresh parsley, chopped
18 - 1 teaspoon dried thyme or Italian herbs
19 - 1/4 teaspoon garlic powder
20 - Pinch of salt

# How-To:

01 - Preheat oven to 400°F. Slice the tops off garlic heads, drizzle with 1 tablespoon olive oil, wrap in foil, and roast for 40 minutes until soft and golden. Allow to cool completely, then squeeze roasted garlic from skins and reserve.
02 - While garlic roasts, heat 1 tablespoon olive oil and butter in a large soup pot over medium-low heat. Add onions, leek, celery, and carrot. Cook, stirring frequently, for 25 to 30 minutes until onions are deeply caramelized and golden brown.
03 - Pour white wine into the pot, scraping up all browned bits from the bottom. Simmer uncovered until liquid is reduced by half, approximately 5 minutes.
04 - Stir roasted garlic, vegetable broth, soy sauce if using, thyme sprigs, bay leaf, and oregano into the pot. Bring to a boil, then reduce heat and simmer uncovered for 25 minutes. Remove thyme sprigs and bay leaf before serving.
05 - Toss bread cubes with 2 tablespoons olive oil, parsley, thyme, garlic powder, and salt. Spread on a baking sheet and bake at 400°F for 10 to 12 minutes, stirring once, until golden and crisp.
06 - Taste soup and adjust salt and pepper as needed. For a smoother texture, blend part or all of the soup using an immersion blender.
07 - Ladle soup into bowls and top with generous portions of herb croutons. Garnish with fresh parsley if desired.

# Expert Advice:

01 -
  • The roasted garlic becomes buttery and mild, so even people who usually push garlic to the side will ask for seconds.
  • It's the kind of soup that tastes like you've been cooking all day, but it actually comes together faster than you'd expect.
  • Those herb croutons add a satisfying crunch that makes the whole bowl feel less like comfort food and more like an event.
02 -
  • Don't skip the step where you stir the onions frequently—I learned this the hard way when I tried to multitask and ended up with burnt edges instead of deep caramelization, and the whole soup suffered for it.
  • The immersion blender is optional but changes the texture completely; whether you blend it or leave it chunky depends on your mood, and both are correct.
03 -
  • Save the roasted garlic skins and use them to infuse olive oil or broth later—they still hold flavor even after roasting.
  • If you're short on time, you can use jarred roasted garlic, but fresh roasted tastes noticeably different and is worth the 40 minutes of oven time.
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