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Soup

Leek or Onion Soup

A creamy soup made with mutton broth, oatmeal or flour, leeks or onions, egg yolks, and served with toasted bread.

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 fully incorporated.

  2. Boil the mixture with leeks or onions until it reaches a creamy consistency.

  3. Alternatively, omit oatmeal and use flour, stirring vigorously for 5 minutes.

  4. Before removing from heat, stir in beaten egg yolks mixed with a little broth.

Serve

  1. Serve immediately with toasted bread seasoned with pepper and salt.

  2. For a refreshing variation, fry chopped onions in oil or butter, pour boiling water over them, and serve.

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

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

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

    Shared aroma: coumarin (sweet, hay).

  4. Leek + breadtop 13% of all pairs
    Smell alikemoderate
    Cooked together279 recipes

    Shared aroma: 1-octen-3-ol (mushroom, earthy).

  5. Egg + breadtop 13% of all pairs
    Smell alikemoderate
    Cooked together22,662 recipes

    Shared aroma: (e)-2-octenal (fatty, green).

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

What each ingredient does

Oatmeal
Thickens the broth into a creamy consistency as it cooks.
Leeks or onions
Add sweetness and aroma as they soften in the broth.
Raw egg yolks
Enrich the soup and thicken it slightly when stirred in off the heat.
Flour (in the method)
Can replace oatmeal as a thickener, stirred vigorously to prevent lumps.

The step that matters

Stir in the egg yolks before removing from heat. Egg yolks thicken when gently heated but can scramble and curdle if they get too hot. Tempering them with a little warm broth first and adding them off the heat keeps the soup smooth and creamy.

Swap the leek

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

  1. Asparagusfits about as well
  2. Capsicumfits about as well
  3. Leekthe original
  4. Potatofits about as well

Fit is the average pairing score against mutton, 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.

More leek soup recipes

Scotch 9Chicken 4Potato 4Welsh 3 See all 47 →

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