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 ↓
Leek S-t O Boil
Ingredients
Directions
Prepare the leeks
Select leeks about the thickness of a finger and cut them to the same length, leaving little green part. Wash and trim them carefully.
Tie the leeks in a bundle and place in a small saucepan with boiling water and a little salt. Parboil for 5 minutes, then drain.
Stew and thicken
Transfer the leeks to a clean saucepan, cover with milk, and add the sugar. Stew until tender, about 20 minutes.
In a separate bowl, knead together the butter and flour. Thicken the milk with this mixture, season to taste, and allow to boil.
Serve
Pour the thickened milk over the leeks and serve on toast.
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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Leek + flourtop 8% of all pairsSmell alikestrongCooked together328 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Flour + milktop 14% of all pairsSmell alikelowCooked together78,219 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Flour + sugartop 15% of all pairsSmell alikemoderateCooked together92,116 recipes
Shared aroma: phenylacetaldehyde (hawthorne, honey).
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
- Leeks
- Form the main body of the stew, becoming soft and tender as they simmer in milk.
- Butter
- Enriches the sauce and carries flavour when kneaded with flour.
- Flour
- Thickens the milk into a smooth, coating sauce when kneaded with butter.
- Milk
- Forms the base of the sauce, which thickens as it is combined with the flour mixture.
- Sugar
- Adds a touch of sweetness that balances the mild onion flavour of the leeks.
The step that matters
Thickening the milk with the butter and flour mixture. Flour needs to be fully blended into the butter and milk and brought to a boil so starch can gelatinise and thicken the sauce. Otherwise lumps form or the sauce stays thin and floury tasting.
Swap the leek
How well each one fits the dish's main ingredients (butter, flour, sugar, milk):
- Arrowrootfits about as well
- Sweet potatofits about as well
- Potatofits about as well
- Leekthe original
Fit is the average pairing score against butter, flour, sugar, milk. 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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