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Sauce

Onion Sauce

A creamy sauce made with butter, flour, milk, mashed onions, parsley, salt, and white pepper.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 7 ingredients
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Why it works: Butter and milk are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 81,283 recipes. Both carry (z)-4-heptenal, which smells biscuit, cream. The science ↓

Onion Sauce

Ingredients

Directions

  1. In a saucepan, cream the flour and butter together.

  2. Gradually add the boiling milk, stirring well.

  3. Mix in the mashed onions, chopped parsley, salt, and white pepper.

  4. Strain the sauce 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. Butter + milktop 7% of all pairs
    Smell alikemoderate
    Cooked together81,283 recipes

    Shared aroma: (z)-4-heptenal (biscuit, cream).

  2. Onion + parsleytop 9% of all pairs
    Smell alikemoderate
    Cooked together25,843 recipes

    Shared aroma: 2,4-decadienal (seaweed).

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

    Shared aroma: isobutyraldehyde (malty, green).

  4. Flour + parsleytop 12% of all pairs
    Smell alikemoderate
    Cooked together16,675 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  5. Parsley + white peppertop 14% of all pairs
    Smell alikelow
    Cooked together1,451 recipes

    Shared aroma: myrcene (balsamic, herbaceous).

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

Butter
Enriches the sauce with fat and rich flavor, and helps the flour form a smooth base.
Flour
Thickens the milk into a smooth sauce as it cooks with the butter.
Milk
Forms the liquid base of the sauce, giving it body and creaminess.
Boiled onions
Add sweet, mellow onion flavor and soft body to the sauce.

The step that matters

Adding the boiling milk. Adding the hot milk gradually while stirring keeps the flour and butter blended into a smooth roux, preventing lumps as the starch thickens the sauce.

Swap the white pepper

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

  1. Capersfits better
  2. Thymefits better
  3. Garlicfits better
  4. White pepperthe original

Fit is the average pairing score against butter, flour, milk, onion, parsley. 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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