Why it works: Celery and pepper match in chemistry and in kitchens. They rank in the top 5% of all ingredient pairs, and cooks put them together in 16,012 recipes. Both carry 4'-methylacetophenone, which smells bitter almond. The science ↓
Split-pea Soup
Ingredients
Directions
Prepare the peas
Wash the peas and soak them overnight in cold water.
Drain the peas and place them in a soup pot with 3 quarts of cold water.
Bring the pot to a boil.
Discard the water.
Add 4 quarts of boiling water to the peas.
Simmer for 4 hours.
Add the celery during the last hour of cooking.
Make the soup
In a separate pan, cook the onion and butter over low heat for 30 minutes.
Drain the peas, saving the cooking water.
Add the drained peas to the pan with onions and butter.
Stir in the flour.
Cook for another 30 minutes, stirring often.
Mash the mixture.
Gradually add the reserved cooking water until the soup is thick and creamy.
Pass the soup through a sieve.
Return to heat, adding salt and pepper.
Cook for an additional 20 minutes.
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.
Explore the science
The flavor team
The pairs that carry this dish. Each one is judged two ways: how much their aromas overlap, and how often cooks already put them together.
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Celery + peppertop 5% of all pairsSmell alikestrongCooked together16,012 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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Onion + celerytop 7% of all pairsSmell alikemoderateCooked together18,518 recipes
Shared aroma: guaiacol (smoky, sweet).
-
Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Peas + celerytop 12% of all pairsSmell alikemoderateCooked together1,832 recipes
Shared aroma: linalool (floral, citrus).
Butter and flour barely smell alike, yet cooks put them together in 124,287 recipes: they 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
- Dried peas
- Break down during long simmering to give the soup its body and thickness.
- Butter
- Carries the onion flavor and adds richness and a silky mouthfeel to the soup.
- Flour
- Thickens the soup by absorbing liquid and helping it hold a creamy consistency.
- Onion
- Adds savory sweetness and aroma as it cooks slowly in the butter.
The step that matters
Gradually add the reserved cooking water. Adding the liquid slowly while mashing lets the flour and pea starch hydrate evenly, preventing lumps and giving a smooth, thick texture rather than a grainy or watery one.
Swap the peas
How well each one fits the dish's main ingredients (onion, butter, flour, celery, pepper):
- Black-eyed peafits better
- Beansfits better
- Lentilsfits better
- Peasthe original
Fit is the average pairing score against onion, butter, flour, celery, pepper. Candidates are from the same food group and used in at least 100 recipes.
“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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