Roasted Garlic Onion Soup (Print)

Slow-roasted garlic and caramelized onions combine with herb croutons for a warm, hearty soup experience.

# Ingredients:

→ 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 & Oils

06 - 4 tablespoons olive oil, divided
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 & 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

# Directions:

01 - Preheat oven to 400°F. Slice 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, then squeeze roasted garlic from skins and reserve.
02 - Heat 1 tablespoon olive oil and butter in a large pot over medium-low heat. Add onions, leek, celery, and carrot. Cook, stirring frequently, until onions are deeply caramelized and golden brown, approximately 25 to 30 minutes.
03 - Deglaze the pot with white wine, scraping up browned bits from the bottom. Simmer until liquid is reduced by half.
04 - Stir in roasted garlic, vegetable broth, soy sauce if using, thyme sprigs, bay leaf, and oregano. 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, dried thyme, garlic powder, and salt. Spread on a baking sheet and bake at 400°F for 10 to 12 minutes, turning once, until golden and crisp.
06 - Taste soup and adjust seasoning with salt and pepper. For a smoother consistency, blend part or all of the soup using an immersion blender.
07 - Ladle soup into bowls and top with herb croutons. Garnish with fresh parsley if desired.

# Expert Tips:

01 -
  • The roasted garlic becomes so mellow and sweet that even garlic skeptics find themselves genuinely enjoying it, which never fails to surprise people at the table.
  • You get to make croutons that stay crisp even after floating in soup for a few minutes, which is honestly harder to pull off than most people realize.
  • The whole pot comes together in just under two hours, meaning you can have something restaurant-quality ready before most people finish their happy hour.
02 -
  • Medium-low heat during onion caramelization isn't a suggestion—high heat will burn them before they sweeten, and you'll end up with bitter soup no matter how good everything else is.
  • Day-old bread for croutons is non-negotiable because fresh bread will absorb the oil and turn into mush instead of staying crisp.
  • Removing the thyme sprigs and bay leaf before serving prevents anyone from accidentally biting into them, which is the kind of small detail that separates good cooking from careless cooking.
03 -
  • Add a pinch of soy sauce right at the end if your soup tastes flat—it won't taste salty, but suddenly everything else will taste more like itself.
  • If you want to make this soup richer, float a small handful of grated Gruyère or Parmesan in each bowl and watch it melt into the hot liquid like a luxury no one expected.
  • The soup is actually better the next day after the flavors have had time to settle and deepen, so don't hesitate to make it ahead.
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