Why it works: Milk and butter are a kitchen classic. They rank in the top 7% of all ingredient pairs, and 81,283 recipes mention both. Both carry (z)-4-heptenal, which smells biscuit, cream. The science ↓
Cream of Tomato Soup
Ingredients
Directions
Make the white sauce
Scald milk with onion, then remove the onion.
Thicken the milk with flour diluted with cold water until it is thin enough to pour, taking care that the mixture is free from lumps.
Cook for twenty minutes, stirring constantly at first.
Prepare the tomatoes
Cook the tomatoes with sugar for fifteen minutes.
Add the soda.
Rub through a sieve.
Combine and serve
Combine the two mixtures.
Strain into a tureen over the butter, salt, and pepper.
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. See the original page.
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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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Milk + buttertop 7% of all pairsAroma overlapmoderateMentioned together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
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Tomato + peppertop 7% of all pairsAroma overlapmoderateMentioned together17,923 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Tomato + oniontop 8% of all pairsAroma overlapmoderateMentioned together20,633 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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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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Flour + buttertop 12% of all pairsAroma overlaplowMentioned together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
Flour and butter share little aroma chemistry, yet 124,287 recipes mention both: they likely 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
- Flour
- Thickens the milk into a smooth, pourable white sauce body.
- Butter
- Adds richness and a silky mouthfeel to the finished soup.
- Milk
- Forms the creamy base that the flour thickens.
- Tomatoes
- Provide the main tomato flavour and body of the soup.
- Sugar
- Balances the acidity of the tomatoes with mild sweetness.
- Baking soda
- Neutralises some tomato acidity, reducing sharpness and curdling risk.
The step that matters
Thicken the milk without lumps. Flour must be fully dispersed in cold water before it meets hot milk; otherwise it clumps as starch swells unevenly. Constant stirring during the first part of cooking keeps the sauce smooth.
Flavor stand-ins for the onion
How well each one fits the dish's main ingredients (tomato, sugar, milk, flour, pepper, butter):
- Capsicumbetter flavor fit
- Potatobetter flavor fit
- Sweet potatobetter flavor fit
- Onionthe original
Fit is the average pairing score against tomato, sugar, milk, flour, pepper, butter. 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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