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 ↓
Gravy or Sauce for a Goose
Ingredients
Directions
Make the gravy
In a pan, melt the butter and add the chopped onion. Cook until it begins to brown.
Stir in the flour and cook for 5 to 6 minutes.
Gradually pour in the brown gravy and let it simmer for 15 minutes.
Strain the mixture and bring it back to a boil.
Finish and serve
Mix the mustard with the port wine and add to the sauce.
Season with cayenne pepper and salt if needed. Do not let the sauce boil after adding the wine.
Serve very hot.
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.
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Onion + mustardtop 6% of all pairsSmell alikestrongCooked together9,259 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Mustard + peppertop 9% of all pairsSmell alikemoderateCooked together15,430 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Flour + mustardtop 13% of all pairsSmell alikemoderateCooked together5,066 recipes
Shared aroma: isobutyraldehyde (malty, green).
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
- Carries the onion and flour, adding richness and a nutty flavor as it browns.
- Onion
- Browning onion adds sweetness and savory depth to the gravy's base.
- Flour
- Cooked with the butter, it thickens the sauce and gives it body.
- Brown gravy
- Forms the liquid base of the sauce, supplying most of its savory flavor.
- Port wine
- Adds sweetness and fruity acidity that balance the savory gravy.
- Made mustard
- Contributes sharp tang and a little heat that cut through the richness.
The step that matters
Do not boil after adding the port wine. Once the wine goes in, prolonged boiling drives off its alcohol and fragile aromas and can make the sauce taste harsh or reduced. Keep it hot but below a boil so the wine's flavor stays bright.
Swap the onion
How well each one fits the dish's main ingredients (butter, flour, mustard, port wine, pepper):
- Shallotfits better
- Horseradishfits better
- Chivefits better
- Onionthe original
Fit is the average pairing score against butter, flour, mustard, port wine, 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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