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Leek or Onion Soup

A creamy soup made from mutton broth, leeks or onions, thickened with oatmeal or flour, finished with beaten egg yolks.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 8 ingredients
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Why it works: Bread and butter are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 27,232 recipes. Both carry delta-decalactone, which smells sweet, creamy. The science ↓

Leek or Onion Soup

Ingredients

Directions

Make the soup

  1. Mix oatmeal with cold water until smooth, then gradually add broth until incorporated.

  2. Boil the mixture with leeks or onions until it thickens to a cream-like consistency.

  3. If using flour, stir it in vigorously for 5 minutes.

Finish and serve

  1. Before serving, stir in the beaten egg yolks mixed with a little broth.

  2. Fry peeled and chopped onions in oil or butter.

  3. Pour boiling water over the fried onions.

  4. Serve the mixture with seasoned toasted bread.

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. Bread + buttertop 7% of all pairs
    Smell alikemoderate
    Cooked together27,232 recipes

    Shared aroma: delta-decalactone (sweet, creamy).

  2. Flour + leektop 8% of all pairs
    Smell alikestrong
    Cooked together328 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  3. Flour + buttertop 12% of all pairs
    Smell alikelow
    Cooked together124,287 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  4. Mutton + breadtop 12% of all pairs
    Smell alikemoderate
    Cooked together1,488 recipes

    Shared aroma: delta-decalactone (sweet, creamy).

  5. Leek + peppertop 12% of all pairs
    Smell alikemoderate
    Cooked together965 recipes

    Shared aroma: coumarin (sweet, hay).

Flour and butter barely smell alike, yet cooks put them together in 124,287 recipes: they work on texture and structure more than aroma.

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

What each ingredient does

Oatmeal or flour
Thickens the broth as its starch swells and sets into a creamy body.
Egg yolks
Enrich the soup and add body when gently heated into the liquid.
Leeks or onions
Add a mild, sweet aroma and savoury body as they cook into the broth.
Oil or butter
Carries fat-soluble flavour when used to fry the onions.

The step that matters

Stir in the egg yolks off the boil. Raw egg yolks thicken by gentle heat and will curdle or scramble if the soup is boiling when they go in. Tempering them with a little warm broth first and adding them before serving keeps the soup smooth and silky.

Swap the leek

How well each one fits the dish's main ingredients (mutton, flour, egg, bread, pepper, butter):

  1. Shallotfits about as well
  2. Leekthe original
  3. Asparagusfits about as well
  4. Chivefits about as well

Fit is the average pairing score against mutton, flour, egg, bread, pepper, butter. 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.

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