Why it works: Butter and bread are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 27,232 recipes. Both carry delta-decalactone, which smells sweet, creamy. The science ↓
Spring Soup
Ingredients
Directions
Prepare the base
Chop the small onions.
Simmer the onions in 1 quart of water until very tender.
Rub the mixture through a sieve.
Season with salt and paprika.
Finish and serve
Thicken the soup with 3 tablespoons of flour and 3 tablespoons of butter mixed together.
Stir in 1 pint of hot milk.
Serve immediately with toasted bread.
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.
-
Butter + breadtop 7% of all pairsSmell alikemoderateCooked together27,232 recipes
Shared aroma: delta-decalactone (sweet, creamy).
-
Butter + milktop 7% of all pairsSmell alikemoderateCooked together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
-
Milk + breadtop 11% of all pairsSmell alikemoderateCooked together11,466 recipes
Shared aroma: 2-undecenal (sweet).
-
Flour + buttertop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
-
Flour + milktop 14% of all pairsSmell alikelowCooked together78,219 recipes
Shared aroma: isobutyraldehyde (malty, green).
Flour and butter 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
- Small onions
- Provide the main flavour and body of the soup once simmered and sieved.
- Flour
- Thickens the soup as it combines with the butter and liquid.
- Butter
- Adds richness and helps the flour blend smoothly into the soup.
- Milk
- Adds creaminess and softens the soup's flavour.
The step that matters
Rub the mixture through a sieve. Onions must be cooked until very tender so they break down easily; pressing them through a sieve yields a smooth texture. Coarse pieces left behind leave the soup grainy.
Swap the onion
How well each one fits the dish's main ingredients (flour, butter, milk, bread):
- Potatofits better
- Leekfits better
- Shallotfits better
- Onionthe original
Fit is the average pairing score against flour, butter, milk, bread. 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.
Indian Spiced Potato Soup with Tofu and Spinach448 recipes
Clear Carrot and Bottle Gourd Soup65 recipes
Mock Bisque Soup51 recipes
Cream of Asparagus Soup42 recipes