Why it works: Mustard and onion 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 ↓
Herrings, Broiled, with Mustard Sauce
Ingredients
Directions
Make the sauce
Fry the onion in the butter until lightly browned.
Add the flour and mustard, then stir in the vinegar and water.
Bring to a boil, then simmer gently for 15 minutes.
Prepare and grill the herrings
Wipe and dry the herrings, then remove the heads.
Score the herrings across the backs and sides, avoiding the roe.
Sprinkle the herrings with salt and pepper.
Grill the herrings over a clear fire for 10 to 15 minutes.
Serve
Place the grilled herrings on a hot dish.
Strain the sauce around the herrings.
Serve.
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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Mustard + oniontop 6% of all pairsSmell alikestrongCooked together9,259 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Mustard + vinegartop 7% of all pairsSmell alikemoderateCooked together14,067 recipes
Shared aroma: isobutyraldehyde (malty, green).
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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).
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Vinegar + oniontop 14% of all pairsSmell alikemoderateCooked together18,226 recipes
Shared aroma: acetic acid (sour, vinegar).
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
- Herrings
- Form the main body of the dish; the grilling cooks the flesh through and firms it.
- Butter
- Carries the onion's flavour and browns lightly, adding richness to the sauce.
- Flour
- Thickens the vinegar and water into a smooth sauce body.
- Mustard
- Adds sharp, pungent flavour that cuts the richness of the fish and butter.
- Vinegar
- Adds acidity that gives the sauce its tang and balances the fat.
- Onion
- Adds savoury sweetness and aroma when fried gently in butter.
The step that matters
Grill over a clear fire for 10 to 15 minutes. Fish cooks quickly and dries out if overcooked, while undercooking leaves the flesh raw near the bone. Watching the heat and timing keeps the herrings moist and fully cooked. Scoring the skin lets heat penetrate evenly so the thick parts cook at the same rate as the thin ones.
Swap the onion
How well each one fits the dish's main ingredients (butter, flour, mustard, vinegar):
- Shallotfits better
- Horseradishfits better
- Radishfits better
- Onionthe original
Fit is the average pairing score against butter, flour, mustard, vinegar. 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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