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 ↓
To Broil Herrings
Ingredients
Directions
Prepare
Scale and gut the herrings, then wash and dry them thoroughly.
Dust the herrings with flour.
Make the sauce
Mash the heads of the herrings and boil them in small beer or ale with whole pepper and onion for 15 minutes.
Strain the mixture, then thicken it with butter and flour, adding mustard to taste.
Cook and serve
Broil the herrings until cooked.
Serve the broiled herrings on a plate with the sauce in a separate dish.
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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Pepper + mustardtop 9% of all pairsSmell alikemoderateCooked together15,430 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Pepper + oniontop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Beer + mustardtop 11% of all pairsSmell alikemoderateCooked together314 recipes
Shared aroma: guaiacol (smoky, sweet).
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Flour + buttertop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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
- Herrings
- Form the main body of the dish, cooking to a tender, flaky texture under the broiler.
- Flour
- Dusts the fish and thickens the sauce together with butter, giving it body.
- Butter
- Enriches the sauce and helps thicken it with flour, adding richness and smooth texture.
- Small beer or ale
- Liquid base for the sauce, extracting flavour from the fish heads, pepper and onion.
- Mustard
- Adds sharp, pungent flavour that balances the richness of the butter sauce.
The step that matters
Broil the herrings until cooked. Fish is dense and cooks quickly, so overcooking dries the flesh and makes it tough. Watch for the flesh turning opaque and flaking easily.
Swap the onion
How well each one fits the dish's main ingredients (flour, butter, beer, pepper, mustard):
- Horseradishfits better
- Shallotfits better
- Chivefits better
- Onionthe original
Fit is the average pairing score against flour, butter, beer, pepper, 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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