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Robert Sauce

A savory sauce made with onion, butter, stock, flour, mustard, vinegar, sugar, lemon juice, salt, and pepper.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 10 ingredients
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Why it works: Lemon and pepper match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 27,047 recipes. Both carry trans-2-nonenal, which smells cardboard, fatty. The science ↓

Robert Sauce

Ingredients

Directions

  1. Melt the butter in a saucepan.

  2. Add the finely chopped onion and fry until it turns pale brown.

  3. Stir in the flour and mix well.

  4. Gradually add the stock, stirring continuously.

  5. Season with salt, pepper, and a pinch of castor sugar.

  6. Simmer for twenty minutes, then pour through a strainer.

  7. Stir in the vinegar, lemon juice, and mustard before serving.

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. Lemon + peppertop 3% of all pairs
    Smell alikestrong
    Cooked together27,047 recipes

    Shared aroma: trans-2-nonenal (cardboard, fatty).

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

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

  3. Mustard + vinegartop 7% of all pairs
    Smell alikemoderate
    Cooked together14,067 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  4. Mustard + peppertop 9% of all pairs
    Smell alikemoderate
    Cooked together15,430 recipes

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

  5. Mustard + lemontop 11% of all pairs
    Smell alikestrong
    Cooked together3,816 recipes

    Shared aroma: eucalyptol (eucalyptus, herbal).

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

What each ingredient does

Butter
Fat that carries the onion flavour and enriches the sauce.
Onion
Adds savoury aroma and flavour as it browns in the butter.
Flour
Thickens the stock into a smooth, lightly bodied sauce.
Stock
Forms the liquid base of the sauce.
Vinegar
Adds acidity that brightens the rich sauce.
French mustard
Adds sharpness and a little pungency to the sauce.

The step that matters

Gradually add the stock, stirring continuously. Adding liquid to the butter and flour mixture gradually while stirring keeps it smooth. Pouring it in all at once can trap lumps of flour that are hard to remove.

Swap the onion

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

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

Fit is the average pairing score against butter, flour, mustard, vinegar, sugar, lemon, 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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