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Sauce

Sauce Robert

A buttery onion sauce flavored with stock, vinegar, mustard, salt, and pepper.

From an old cookbook · modernised transcription
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Why it works: Onion and mustard match in chemistry and in kitchens. They rank in the top 6% of all ingredient pairs, and cooks put them together in 9,259 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Sauce Robert

Ingredients

Directions

Make the sauce

  1. Melt a piece of butter in a pan large enough to fry the onions.

  2. Add the onions and cook until browned.

  3. Dilute the browned onions with some stock, skimming occasionally.

  4. Let the sauce boil for half an hour.

Finish and serve

  1. Before serving, add coarse sea salt, black pepper, a little vinegar, and some mustard.

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. Onion + mustardtop 6% of all pairs
    Smell alikestrong
    Cooked together9,259 recipes

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

  2. Vinegar + mustardtop 7% of all pairs
    Smell alikemoderate
    Cooked together14,067 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  3. Pepper + mustardtop 9% of all pairs
    Smell alikemoderate
    Cooked together15,430 recipes

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

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

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

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

    Shared aroma: acetic acid (sour, vinegar).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

What each ingredient does

Onions
Browning them builds the deep, savoury flavour that forms the base of the sauce.
Stock
Provides the liquid that dilutes the onions and becomes the body of the sauce.
Butter
Fat for frying the onions, adding richness and helping them brown evenly.
Vinegar
Adds acidity that brightens the sauce and balances its richness.
Mustard
Adds sharp, pungent flavour that gives the sauce its characteristic bite.

The step that matters

Browning the onions. Onions must be cooked until well browned, because the Maillard reaction and caramelisation create the deep flavour the sauce depends on. Pale onions leave the sauce tasting flat.

Swap the onion

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

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

Fit is the average pairing score against butter, pepper, vinegar, mustard. 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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