Why it works: Pepper and lemon match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and 27,047 recipes mention both. Both carry trans-2-nonenal, which smells cardboard, fatty. The science ↓
Tomato Soup
Ingredients
Directions
Make the soup
In a saucepan, combine the tomatoes, butter, sliced onion, and bay leaf.
Cook gently until the tomatoes are thoroughly done.
Strain the mixture through a wire sieve.
Add 1 pint of good stock to the strained mixture.
Finish and serve
Just before serving, stir in lemon juice, pepper, and salt to taste.
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 + lemontop 3% of all pairsAroma overlapstrongMentioned together27,047 recipes
Shared aroma: trans-2-nonenal (cardboard, fatty).
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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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Tomato + lemontop 11% of all pairsAroma overlapmoderateMentioned together4,592 recipes
Shared aroma: 3-hexenal (apple, fruity).
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Pepper + oniontop 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
- Tomatoes
- Provide the main body, flavor, and color of the soup once cooked down and strained.
- Butter
- Adds richness and a rounder mouthfeel to the tomato base.
- Onion
- Adds savory sweetness and aromatic depth as it softens during gentle cooking.
- Stock
- Thins the strained tomato base and adds savory body.
- Lemon juice
- Adds acidity that brightens the flavor of the tomatoes.
The step that matters
Cook gently until the tomatoes are thoroughly done. Gentle heat softens the tomatoes and lets their flavor concentrate without scorching the butter or sugars, so the strained soup tastes rich rather than burnt or thin.
Flavor stand-ins for the onion
How well each one fits the dish's main ingredients (tomato, butter, pepper, lemon):
- Capsicumbetter flavor fit
- Okrabetter flavor fit
- Spinachbetter flavor fit
- Onionthe original
Fit is the average pairing score against tomato, butter, pepper, lemon. 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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