Why it works: Butter and bread are a kitchen classic. They rank in the top 7% of all ingredient pairs, and 27,232 recipes mention both. Both carry delta-decalactone, which smells sweet, creamy. The science ↓
Tomato Soup
Ingredients
Directions
Make the soup
Fry the onions in butter until golden.
Transfer onions to a stewpan with more butter, salt, and pepper.
Cut tomatoes into pieces and add to the stewpan, including their juice.
Simmer for 10 minutes.
Add stock or water and bring to a boil.
Cook slowly for 45 minutes.
Finish and serve
Pass the soup through a fine sieve.
Serve with fried bread or croutons.
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.
Photo for illustrative purposes only · Contact us to use it
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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Butter + breadtop 7% of all pairsAroma overlapmoderateMentioned together27,232 recipes
Shared aroma: delta-decalactone (sweet, creamy).
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Pepper + tomatotop 7% of all pairsAroma overlapmoderateMentioned together17,923 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Onion + tomatotop 8% of all pairsAroma overlapmoderateMentioned together20,633 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Tomato + breadtop 10% of all pairsAroma overlapmoderateMentioned together1,013 recipes
Shared aroma: 2-nonenal (fatty, green).
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Onion + peppertop 11% of all pairsAroma overlapmoderateMentioned together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Onions
- Fried until golden, they build a sweet, savory base for the soup.
- Tomatoes
- They supply the main body, acidity and flavor of the soup.
- Butter
- Fat carries flavor and gives the onions their golden browning.
- Stock
- Liquid that thins the tomato mixture and carries flavor through the soup.
The step that matters
Cook slowly for 45 minutes. A gentle simmer lets the tomatoes break down and their flavor concentrate. Boiling hard can scorch the bottom of the pan and make the soup taste harsh.
Flavor stand-ins for the onion
How well each one fits the dish's main ingredients (butter, pepper, tomato, bread):
- Capsicumbetter flavor fit
- Potatobetter flavor fit
- Carrotabout as good a flavor fit
- Onionthe original
Fit is the average pairing score against butter, pepper, tomato, bread. Candidates are from the same food group and used in at least 100 recipes. This compares flavor only: it does not check the job the ingredient does in the dish (bulk, moisture, acidity, structure).
“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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