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Sauce

Plain Onion or Caper Sauce

A sauce made from cooked onions or capers, thickened with flour and water, seasoned with salt, vinegar, and optional butter.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 7 ingredients
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Why it works: Flour and capers match in chemistry and in kitchens. They rank in the top 6% of all ingredient pairs, and cooks put them together in 1,024 recipes. Both carry isobutyraldehyde, which smells malty, green. The science ↓

Plain Onion or Caper Sauce

Ingredients

Directions

Make the base

  1. Mix the flour with a little cold water until smooth.

  2. Gradually add the ½ pint of water from the cooked meat, stirring well.

  3. Pour the mixture into a small saucepan and bring to a boil, adding salt to taste.

Add the flavourings

  1. For Caper Sauce, cut the capers in half and add them along with the vinegar.

  2. For Onion Sauce, boil the onions in two waters until soft, then chop finely.

  3. Stir the chopped onions into the sauce.

  4. If desired, add 1 ounce of butter for a richer sauce.

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 + caperstop 6% of all pairs
    Smell alikestrong
    Cooked together1,024 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  2. Onion + caperstop 7% of all pairs
    Smell alikestrong
    Cooked together1,381 recipes

    Shared aroma: coumarin (sweet, hay).

  3. Capers + saucetop 11% of all pairs
    Smell alikemoderate
    Cooked together678 recipes

    Shared aroma: ethanol (alcoholic, ethereal).

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

    Shared aroma: isobutyraldehyde (malty, green).

  5. Onion + vinegartop 14% of all pairs
    Smell alikemoderate
    Cooked together18,226 recipes

    Shared aroma: acetic acid (sour, vinegar).

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
Starch that thickens the liquid into a smooth, body-rich sauce as it heats.
Cooked onions
Soft, chopped onions add body and mild sweetness to the sauce.
Capers
Briny, sharp pieces that give the sauce its characteristic savoury bite.
Vinegar
Adds acidity that brightens the sauce and balances its richness.
Butter
Adds fat that makes the sauce feel richer and smoother on the palate.

The step that matters

Mixing the flour into cold water before adding the hot liquid. Starch granules must be separated in cold liquid before heating, or they clump into lumps. Stirring steadily as the sauce comes to a boil lets the starch swell and thicken evenly.

Swap the onion

How well each one fits the dish's main ingredients (flour, meat, capers, sauce, vinegar, butter):

  1. Shallotfits better
  2. Mustardfits better
  3. Horseradishfits better
  4. Onionthe original

Fit is the average pairing score against flour, meat, capers, sauce, vinegar, 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.

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