Why it works: Tomato and pepper are a kitchen classic. They rank in the top 7% of all ingredient pairs, and 17,923 recipes mention both. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Tomato Soup
Ingredients
Directions
Prepare
Chop the onion finely.
Cook the tomatoes and onion in enough water to make ½ pint of soup for 15 minutes.
Rub the vegetables through a sieve and return to the saucepan.
Finish and serve
Bring to a boil, thicken with cornflour mixed with a spoonful of water, and add butter.
Serve with toasted bread pieces.
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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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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Onion + buttertop 15% of all pairsAroma overlapmoderateMentioned together42,912 recipes
Shared aroma: decanal (soap, orange peel).
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Pepper + buttertop 21% of all pairsAroma overlapmoderateMentioned together85,593 recipes
Shared aroma: trans-2-nonenal (cardboard, fatty).
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, flavour and colour of the soup.
- Cornflour
- Thickens the soup as it heats, giving it a smoother body.
- Onion
- Adds savoury sweetness and aromatic depth as it softens in the liquid.
- Butter
- Adds fat for a richer mouthfeel and a silkier finish.
The step that matters
Thickening with cornflour. Cornflour must be mixed into a little cold water first so it does not clump, then stirred into the simmering soup. Starch thickens only once it is heated, so the soup should be brought to a boil and stirred until it visibly thickens.
Flavor stand-ins for the onion
How well each one fits the dish's main ingredients (tomato, pepper, butter):
- Capsicumbetter flavor fit
- Potatobetter flavor fit
- Carrotabout as good a flavor fit
- Onionthe original
Fit is the average pairing score against tomato, 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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