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Sauce

White Onion Sauce

A creamy sauce made from boiled white onions, butter, flour, salt, and cream or milk.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 5 ingredients
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Why it works: Butter and cream are a kitchen classic. They rank in the top 8% of all ingredient pairs, and cooks put them together in 41,516 recipes. Both carry delta-dodecalactone, which smells sweet, creamy. The science ↓

White Onion Sauce

Ingredients

Directions

Prepare the onions

  1. Peel and halve the onions, then soak them in spring water for 15 minutes.

  2. Boil the onions in fresh water for about 45 minutes or until tender.

  3. Drain the onions and chop them finely.

Make the sauce

  1. In a clean saucepan, melt the butter and stir in the flour.

  2. Add the chopped onions, salt, and cream or milk, stirring until it boils.

  3. Rub the mixture through a sieve, adding more cream or milk to reach your desired consistency.

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. Butter + creamtop 8% of all pairs
    Smell alikemoderate
    Cooked together41,516 recipes

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

  2. Butter + flourtop 12% of all pairs
    Smell alikelow
    Cooked together124,287 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  3. Onion + buttertop 15% of all pairs
    Smell alikemoderate
    Cooked together42,912 recipes

    Shared aroma: decanal (soap, orange peel).

  4. Onion + flourtop 17% of all pairs
    Smell alikemoderate
    Cooked together32,460 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  5. Onion + creamtop 18% of all pairs
    Smell alikelow
    Cooked together10,827 recipes

    Shared aroma: 2-nonanone (fruity, floral).

Butter and flour 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

White onions
Provide the bulk and sweet, mild onion flavour that forms the sauce.
Butter
Adds richness and carries flavour as the base of the roux.
Flour
Thickens the sauce when cooked with butter into a roux.
Cream or milk
Adds moisture and smoothness, making the sauce creamy and adjustable in thickness.

The step that matters

Stirring the sauce as it comes to a boil. Flour thickens only when heated with liquid, and it can clump or scorch if not stirred. Constant stirring keeps the sauce smooth and prevents the dairy from sticking and burning on the pan base.

Swap the onion

How well each one fits the dish's main ingredients (butter, flour, cream):

  1. Leekfits better
  2. Arrowrootfits better
  3. Chivefits better
  4. Onionthe original

Fit is the average pairing score against butter, flour, cream. 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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