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Leek or Onion Soup

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

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 7 ingredients
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Why it works: Flour and leek match in chemistry and in kitchens. They rank in the top 8% of all ingredient pairs, and cooks put them together in 328 recipes. Both carry isobutyraldehyde, which smells malty, green. The science ↓

Leek or Onion Soup

Ingredients

Directions

Make the soup base

  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 thickens to a creamy 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 chopped onions in oil or butter. Pour boiling water over them.

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

    Shared aroma: isobutyraldehyde (malty, green).

  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.
Egg yolks
Enrich the soup and give it a richer, smoother body when stirred in.
Leeks or onions
Add sweetness and savoury flavour to the broth as it boils.

The step that matters

Stirring in the egg yolks. Egg yolks can scramble if added to very hot liquid. Mixing them with a little broth first and adding them off the heat, before serving, helps them blend smoothly and thicken gently.

Swap the leek

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

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

Fit is the average pairing score against mutton, flour, egg, bread, 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 leek soup recipes

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

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