Why it works: Butter and bread are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 27,232 recipes. Both carry delta-decalactone, which smells sweet, creamy. The science ↓
Onion Soup
Ingredients
Directions
In a stew pan, melt the butter over medium heat.
Add the sliced onions and sugar, cooking until they turn golden brown.
Pour in the broth and bring to a simmer.
Add the bread and cook for a few more minutes.
Before serving, stir in the Cognac brandy.
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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Butter + breadtop 7% of all pairsSmell alikemoderateCooked together27,232 recipes
Shared aroma: delta-decalactone (sweet, creamy).
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Butter + cognac brandytop 13% of all pairsSmell alikemoderateCooked together162 recipes
Shared aroma: trans-2-nonenal (cardboard, fatty).
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Onion + buttertop 15% of all pairsSmell alikemoderateCooked together42,912 recipes
Shared aroma: decanal (soap, orange peel).
-
Onion + breadtop 15% of all pairsSmell alikemoderateCooked together8,676 recipes
Shared aroma: 2,4-decadienal (seaweed).
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Butter + sugartop 17% of all pairsSmell alikemoderateCooked together98,233 recipes
Shared aroma: guaiacol (smoky, sweet).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Onions
- Caramelize into sweet, deep-flavoured base as their sugars brown.
- Butter
- Carries fat for browning the onions and adds rich flavour.
- Broth
- Forms the liquid body of the soup and carries flavour.
- Bread
- Soaks up broth and thickens the soup slightly as it cooks.
- Cognac brandy
- Adds aromatic depth when stirred in near the end.
The step that matters
Browning the onions. Onions need slow, steady cooking over medium heat to turn golden brown. Rushing with high heat scorches the sugars and makes the soup bitter, while too little browning leaves it flat.
Swap the onion
How well each one fits the dish's main ingredients (butter, sugar, bread, cognac brandy):
- Shallotfits better
- Capsicumfits better
- Tomatofits about as well
- Onionthe original
Fit is the average pairing score against butter, sugar, bread, cognac brandy. 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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