Why it works: Butter and milk 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
The book gives no cooking times; the times in the steps were added in transcription, so check for doneness rather than trusting the clock.
In a pot, melt butter and sauté chopped onion until soft.
Add canned tomatoes and cook for 10 minutes.
Stir in flour and cook for 2 minutes.
Gradually add milk, stirring constantly until thickened.
Season with salt and pepper to taste.
Blend until smooth and serve hot.
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 + milktop 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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Butter + flourtop 12% of all pairsAroma overlaplowMentioned together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
Butter and flour 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
- Canned tomatoes
- Provide the main body and tomato flavour of the soup.
- Onion
- Adds savoury sweetness and aroma as it softens in butter.
- Butter
- Carries flavour from the onion and adds richness to the soup.
- Flour
- Thickens the soup as it cooks with the butter and liquid.
- Milk
- Adds creaminess and, with the flour, forms a thickened base.
The step that matters
Gradually add milk, stirring constantly until thickened. Adding milk all at once can leave lumps of flour. Stirring constantly while adding it slowly lets the starch disperse evenly and thicken the soup smoothly.
Flavor stand-ins for the onion
How well each one fits the dish's main ingredients (tomato, butter, flour, milk, pepper):
- Capsicumbetter flavor fit
- Potatobetter flavor fit
- Okrabetter flavor fit
- Onionthe original
Fit is the average pairing score against tomato, butter, flour, milk, pepper. 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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