Why it works: Butter and milk are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 81,283 recipes. Both carry (z)-4-heptenal, which smells biscuit, cream. The science ↓
Green Pea Soup
Ingredients
Directions
Prepare the peas
Cover the green peas with hot water.
Boil the peas with the onion until they can be easily mashed.
Mash the peas.
Add the stock or water to the mashed peas.
Make the soup
In a separate pan, cook the butter and flour together until smooth but not browned.
Add the butter and flour mixture to the peas.
Stir in the cream and milk.
Season with salt and pepper to taste.
Let the soup boil briefly.
Strain the soup.
Serve hot, adding whipped cream just before serving if desired.
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.
-
Butter + milktop 7% of all pairsSmell alikemoderateCooked together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
-
Butter + creamtop 8% of all pairsSmell alikemoderateCooked together41,516 recipes
Shared aroma: delta-dodecalactone (sweet, creamy).
-
Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
-
Peas + oniontop 13% of all pairsSmell alikemoderateCooked together5,460 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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
- Green peas
- Form the main body and flavor of the soup once mashed.
- Butter and flour
- Cooked together into a roux that thickens the soup and gives it body.
- Cream
- Adds richness and a smooth, velvety texture.
- Milk
- Adds creaminess and moisture, softening the soup's body.
The step that matters
Cooking the butter and flour until smooth but not browned. The roux must cook long enough to lose its raw flour taste while staying pale, since browning changes the color and flavor and uneven cooking leaves lumps that prevent a smooth, thickened soup.
Swap the peas
How well each one fits the dish's main ingredients (onion, butter, flour, cream, milk, pepper):
- Almondfits better
- Chestnutfits better
- Cashew nutfits better
- Peasthe original
Fit is the average pairing score against onion, butter, flour, cream, milk, 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.
You might also like
The free Flavor Lab newsletter: one surprising pairing a week and the molecular reason it works, in 60 seconds. No spam, unsubscribe anytime.
Prefer an account? Create a free account to save pairings and unlock the full chemistry.

Green Peas229 recipes
Green Peas Soup35 recipes
Tomato Soup526 recipes
Brown Bread461 recipes