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 ↓
Marrow Soup
Ingredients
Directions
Boil the chopped onions in enough water to cover them for 1 hour.
Add the small pieces of marrow and boil for another hour, adding more water if necessary.
Pass the mixture through a wire sieve or mash it very fine with a wooden spoon.
Return the mixture to the saucepan and stir in the milk mixed with the wholemeal flour, butter, pepper, salt, and nutmeg or mace.
Boil for 15 minutes, then serve.
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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Butter + milktop 7% of all pairsSmell alikemoderateCooked together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
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Pepper + nutmegtop 7% of all pairsSmell alikestrongCooked together13,015 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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Flour + nutmegtop 8% of all pairsSmell alikemoderateCooked together18,623 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Flour + buttertop 12% of all pairsSmell alikelowCooked together124,287 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
- Marrow
- Forms the bulk of the soup and, once cooked and puréed, gives it body and a mild sweet flavour.
- Spanish onions
- Soften during long boiling and add sweetness and savoury depth to the base.
- Wholemeal flour
- Mixed with the milk and stirred in to thicken the soup slightly.
- Butter
- Adds richness and a smoother mouthfeel to the finished soup.
- Milk
- Adds creaminess and softens the flavour of the vegetable purée.
The step that matters
Passing the mixture through a sieve or mashing it very fine. Cooked marrow and onion are soft and fibrous; a fine purée gives the smooth texture the soup depends on, and any coarse pieces will feel stringy.
Swap the onion
How well each one fits the dish's main ingredients (flour, butter, milk, pepper, nutmeg):
- Potatofits better
- Capsicumfits better
- Shallotfits better
- Onionthe original
Fit is the average pairing score against flour, butter, milk, pepper, nutmeg. 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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