Why it works: Pepper and parsley match in chemistry and in kitchens. They rank in the top 2% of all ingredient pairs, and 34,122 recipes mention both. Both carry 4'-methylacetophenone, which smells bitter almond. The science ↓
Cream of Tomato Soup
Ingredients
Directions
Make the tomato base
Cook the tomatoes for a few minutes.
Strain the tomatoes.
Return the strained tomatoes to the stove.
Add butter to the tomatoes.
Add salt to the tomatoes.
Add pepper to the tomatoes.
Add a little baking soda to the tomatoes.
Thicken the mixture with flour until quite thick.
Add the remaining baking soda to the tomatoes.
Add a little minced parsley to the tomatoes.
Add the milk and serve
Heat the milk separately in a double boiler until boiling hot.
Add the boiling milk to the soup.
Serve in heated soup bowls.
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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Pepper + parsleytop 2% of all pairsAroma overlapstrongMentioned together34,122 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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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 + parsleytop 8% of all pairsAroma overlapmoderateMentioned together5,398 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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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 tangy flavour of the soup.
- Milk
- Adds creaminess and smooth richness to the soup.
- Flour
- Thickens the soup so it becomes quite thick.
- Butter
- Adds fat for richer flavour and a smoother mouthfeel.
- Baking soda
- Neutralises some tomato acidity, which helps keep the milk from curdling.
The step that matters
Adding the boiling milk to the tomatoes. Tomatoes are acidic, and adding cold or very hot milk to acidic liquid can cause the milk proteins to curdle. Heating the milk separately and adding it to a base that has been made less acidic with baking soda helps keep the soup smooth.
Flavor stand-ins for the parsley
How well each one fits the dish's main ingredients (tomato, milk, butter, pepper, flour):
- Cinnamonabout as good a flavor fit
- Cardamomabout as good a flavor fit
- Thymeabout as good a flavor fit
- Parsleythe original
Fit is the average pairing score against tomato, milk, butter, pepper, flour. 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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