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Caramelized Onion Red Lentil Soup

Caramelized Onion Red Lentil Soup Recipe

Olivia Brooks
This Caramelized Onion Red Lentil Soup uses onions, garlic, lentils, and turmeric for a rich, velvety texture and deep flavor in every comforting spoonful.
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Prep Time 15 minutes
Cook Time 40 minutes
Total Time 55 minutes
Course Soup
Cuisine American
Servings 4 bowls
Calories 280 kcal

Equipment

  • Large pot or Dutch oven
  • Wooden spoon
  • Sharp knife and cutting board.
  • Measuring cups and spoons.
  • Ladle
  • Immersion blender or regular blender (optional)

Ingredients
  

  • 3 large onions thinly sliced
  • 2 tablespoons olive oil
  • 3 cloves garlic minced
  • 1 cup red lentils rinsed
  • 4 cups vegetable broth
  • 1 teaspoon ground cumin
  • 1/2 teaspoon turmeric
  • 1/2 teaspoon black pepper
  • 1 teaspoon salt adjust to taste
  • 1 tablespoon lemon juice
  • Optional: chili flakes for heat

Instructions
 

Step 1: Caramelize the Onions

  • Heat olive oil in a large pot over medium-low heat. Add the sliced onions and cook slowly for 20–25 minutes, stirring occasionally. The onions should turn deep golden brown and become soft and slightly sticky.
  • This is the most important step—don’t rush it. The flavor of the entire soup depends on properly caramelized onions.

Step 2: Add Garlic

  • Stir in the minced garlic and cook for about 1 minute until fragrant. Be careful not to burn it.

Step 3: Add Spices

  • Add cumin, turmeric, salt, and black pepper. Stir well so the spices coat the onions evenly.

Step 4: Add Lentils and Broth

  • Add the rinsed red lentils and vegetable broth. Stir everything together and bring to a gentle boil.

Step 5: Simmer

  • Reduce the heat and let the soup simmer for 15–20 minutes, or until the lentils are soft and fully cooked.

Step 6: Blend (Optional)

  • If you prefer a smoother texture, blend the soup partially or fully. I personally like a slightly textured consistency—it feels more rustic and comforting.

Step 7: Finish with Lemon Juice

  • Stir in the lemon juice and taste. Adjust seasoning if needed.

Step 8: Serve

  • Ladle into bowls and garnish with chili flakes or a drizzle of olive oil.

Notes

  • Be patient with the onions—this is where the magic happens
  • Keep the heat low to avoid burning
  • Stir occasionally, not constantly
  • Taste and adjust seasoning at the end
Keyword Caramelized Onion Red Lentil Soup