Caramelized Onion Red Lentil Soup (Printable)

Rich, comforting vegetarian soup with deeply caramelized onions, hearty red lentils, and fragrant spices.

# What You'll Need:

→ Vegetables

01 - 3 large yellow onions, thinly sliced
02 - 2 cloves garlic, minced
03 - 2 medium carrots, diced
04 - 1 stalk celery, diced

→ Lentils & Staples

05 - 1 cup dried red lentils, rinsed
06 - 6 cups vegetable broth

→ Spices & Seasonings

07 - 2 tbsp olive oil
08 - 1 bay leaf
09 - 1 tsp ground cumin
10 - 1/2 tsp smoked paprika
11 - 1/4 tsp ground black pepper
12 - 1/2 tsp dried thyme
13 - 1–1.5 tsp salt, to taste

→ Garnish (optional)

14 - Chopped fresh parsley
15 - Lemon wedges

# Directions:

01 - In a large soup pot, heat olive oil over medium-low heat. Add sliced onions and a pinch of salt. Cook, stirring occasionally, for 20–25 minutes until onions are deeply golden and caramelized.
02 - Add garlic, carrots, and celery. Sauté for 3–4 minutes until slightly softened.
03 - Stir in cumin, smoked paprika, black pepper, thyme, and bay leaf. Cook for 1 minute until fragrant.
04 - Add rinsed red lentils and vegetable broth. Bring to a boil, then reduce heat to a simmer. Cook uncovered for 15–20 minutes, or until lentils and vegetables are soft.
05 - Remove bay leaf. Use an immersion blender to blend soup partially or fully, depending on desired texture.
06 - Taste and adjust salt and pepper as needed. Serve hot, garnished with fresh parsley and a squeeze of lemon juice if desired.

# Expert Tips:

01 -
  • The caramelized onions create a depth of flavor that feels like this has been simmering all day
  • Red lentils break down beautifully, making the soup naturally creamy without any dairy
  • It is one of those rare soups that tastes even better the next day
02 -
  • Rushing the onion caramelization is the biggest mistake you can make with this recipe
  • Red lentils vary in how quickly they break down, so check for doneness a few minutes early
  • The soup thickens considerably as it sits, so thin with extra broth when reheating
03 -
  • Keep the heat relatively low while caramelizing onions to prevent burning
  • Let the soup cool slightly before blending to avoid splatters

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