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Onion Sauce

A sauce made with flour, butter, boiling milk, chopped onions, salt, and pepper.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 6 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

Make the sauce

  1. Mix flour and butter until light.

  2. Gradually add boiling milk, stirring constantly until it boils.

  3. Stir in chopped onions.

  4. Season with salt and pepper to taste.

Serve

  1. Serve with boiled veal, poultry, or mutton.

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 + peppertop 11% of all pairs
    Smell alikemoderate
    Cooked together68,474 recipes

    Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).

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

    Shared aroma: isobutyraldehyde (malty, green).

  4. Flour + milktop 14% of all pairs
    Smell alikelow
    Cooked together78,219 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  5. Butter + oniontop 15% of all pairs
    Smell alikemoderate
    Cooked together42,912 recipes

    Shared aroma: decanal (soap, orange peel).

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

Flour
Thickens the sauce as its starch swells and sets when heated in the liquid.
Butter
Adds fat for richness and a smooth, silky mouthfeel to the sauce.
Milk
Forms the liquid base, and its milk solids give the sauce a creamy body.
Onions
Contribute savory aroma and flavor, and small pieces add texture to the sauce.

The step that matters

Gradually add boiling milk, stirring constantly. Flour starch must be dispersed evenly in the fat and liquid. Adding the milk slowly while stirring prevents lumps, and constant stirring lets the starch thicken evenly as the sauce heats to a boil.

Swap the onion

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

  1. Potatofits better
  2. Capsicumfits better
  3. Chivefits better
  4. Onionthe original

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

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