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Lentil Soup

A hearty soup made with red lentils, carrots, turnip, parsnip, onions or leeks, and seasoned with pepper and sea salt.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 9 ingredients
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Why it works: Turnip and parsnip match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 590 recipes. Both carry coumarin, which smells sweet, hay. The science ↓

Lentil Soup

Ingredients

Directions

Prepare the lentils

  1. Wash the lentils in several waters until perfectly clean.

  2. Soak the lentils overnight in cold water.

Cook

  1. In a pot, bring 10 cups of water to a boil.

  2. Add the soaked lentils and chopped vegetables along with a pinch of baking soda.

  3. Boil for 2 hours.

Strain and serve

  1. Strain the mixture through a colander, rubbing the lentils through while discarding the skins.

  2. Return the soup to the pot to warm it up.

  3. Season with pepper and coarse sea salt to taste.

  4. Serve very hot.

Recipe from a historical cookbook (Internet Archive).

Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.

Explore the science

The flavor team

The pairs that carry this dish. Each one is judged two ways: how much their aromas overlap, and how often cooks already put them together.

  1. Turnip + parsniptop 1% of all pairs
    Smell alikestrong
    Cooked together590 recipes

    Shared aroma: coumarin (sweet, hay).

  2. Carrot + parsniptop 1% of all pairs
    Smell alikestrong
    Cooked together1,097 recipes

    Shared aroma: 2-isobutyl-3-methoxypyrazine (green bell pepper, earthy).

  3. Lentils + turniptop 1% of all pairs
    Smell alikestrong
    Cooked together109 recipes

    Shared aroma: coumarin (sweet, hay).

  4. Lentils + parsniptop 1% of all pairs
    Smell alikestrong
    Cooked together42 recipes

    Shared aroma: coumarin (sweet, hay).

  5. Carrot + turniptop 1% of all pairs
    Smell alikestrong
    Cooked together8,002 recipes

    Shared aroma: coumarin (sweet, hay).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

What each ingredient does

Red lentils
Form the body of the soup, thickening it as they break down during long boiling.
Onions or leeks
Add savory sweetness and aroma as they soften into the broth.
Carrot
Adds natural sweetness and color while softening into the soup.
Baking soda
Raises the pH of the cooking water, helping lentils soften faster and break down.

The step that matters

Rubbing the lentils through the strainer. Pressing the cooked lentils and vegetables through the colander separates the pulp from the skins. Discarding the skins leaves a smooth, thick soup instead of a grainy or husky texture.

Swap the onion

How well each one fits the dish's main ingredients (lentils, carrot, turnip, parsnip, pepper):

  1. Leekfits better
  2. Beetrootfits better
  3. Kalefits better
  4. Onionthe original

Fit is the average pairing score against lentils, carrot, turnip, parsnip, pepper. Candidates are from the same food group and used in at least 100 recipes.

“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.

More lentil soup recipes

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