Why it works: Butter and flour are a kitchen classic. They rank in the top 12% of all ingredient pairs, and cooks put them together in 124,287 recipes. Both carry isobutyraldehyde, which smells malty, green. The science ↓
Pea Soup
Ingredients
Directions
Cook the peas
Soak the dried peas in cold water.
Cook the peas, adding ½ cup of cold water every 15 minutes until soft.
Mash the peas through a fine colander.
Thicken the soup
Melt the butter and flour together until smooth in a separate saucepan.
Gradually add the strained pea soup to the butter and flour mixture, stirring to combine.
Finish
Add meat bones after the peas start boiling.
Fry the onion in the saucepan before adding the peas.
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 their aromas overlap, and how often cooks already put them together.
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Peas + oniontop 13% of all pairsSmell alikemoderateCooked together5,460 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Butter + oniontop 15% of all pairsSmell alikemoderateCooked together42,912 recipes
Shared aroma: decanal (soap, orange peel).
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Peas + buttertop 16% of all pairsSmell alikemoderateCooked together4,887 recipes
Shared aroma: trans-2-nonenal (cardboard, fatty).
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Butter + meattop 16% of all pairsSmell alikemoderateCooked together7,594 recipes
Shared aroma: guaiacol (smoky, sweet).
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 split yellow peas
- Provide the main body and starchy structure that gives the soup its thickness.
- Butter
- Adds richness and a fat base for cooking the flour smoothly.
- Flour
- Thickens the soup as its starch swells when heated with the melted butter.
The step that matters
Gradually add the strained soup to the butter and flour mixture. Flour starch clumps when liquid is poured in all at once. Adding the liquid slowly while stirring lets the starch disperse evenly in the fat, giving a smooth, lump-free thickened soup.
Swap the onion
The recipe marks onion as optional. How well each one fits the dish's main ingredients (peas, butter, flour, meat):
- Shallotfits better
- Asparagusfits better
- Leekfits better
- Onionthe original
Fit is the average pairing score against peas, butter, flour, meat. 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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