Why it works: Onion and pepper are a kitchen classic. They rank in the top 11% of all ingredient pairs, and 68,474 recipes mention both. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Onion Soup with Water
Ingredients
Directions
Heat the grease in a stewpan and add the sliced onions. Cook until they are half brown.
Sift in the flour or bread crumbs and continue to brown well.
Add the boiling water, salt, pepper, and cold cooked vegetables.
Fry the small pieces of bread in grease until brown in a separate pan, then add them to the soup.
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 aroma chemistry they share, and how many recipes mention both.
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Onion + peppertop 11% of all pairsAroma overlapmoderateMentioned together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Onion + breadtop 15% of all pairsAroma overlapmoderateMentioned together8,676 recipes
Shared aroma: 2,4-decadienal (seaweed).
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Pepper + breadtop 16% of all pairsAroma overlapmoderateMentioned together20,964 recipes
Shared aroma: 2-nonenal (fatty, green).
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Onion + flourtop 17% of all pairsAroma overlapmoderateMentioned together32,460 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Flour + peppertop 19% of all pairsAroma overlapmoderateMentioned together50,459 recipes
Shared aroma: isobutyraldehyde (malty, green).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Onions
- Browning in the fat builds the sweet, deep flavour that defines the soup.
- Flour or fine bread crumbs
- Browned with the onions, it thickens the soup and adds a toasted flavour.
- Grease or oil
- Carries heat to the onions so they brown evenly instead of steaming.
- Cold cooked vegetables
- Add body and substance to the broth.
The step that matters
Browning the onions and flour. Onions must be browned, not just softened, to develop sweetness and colour. Stirring in the flour and browning it well cooks out its raw taste and gives the soup its body and colour.
“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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