Why it works: Potato and onion are a kitchen classic. They rank in the top 3% of all ingredient pairs, and cooks put them together in 9,023 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Lyonnaise Potatoes
Ingredients
Directions
Prepare
Slice the cold boiled potatoes.
Mince the onion and parsley finely.
Fry
Melt the butter in a frying pan.
Add the onion and fry until light brown.
Add the potatoes and fry until light brown, turning often.
Serve
Transfer to a hot dish, stir in the minced parsley, and pour any remaining butter from the pan over the potatoes.
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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Potato + oniontop 3% of all pairsSmell alikemoderateCooked together9,023 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Potato + parsleytop 5% of all pairsSmell alikemoderateCooked together2,855 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
-
Onion + parsleytop 9% of all pairsSmell alikemoderateCooked together25,843 recipes
Shared aroma: 2,4-decadienal (seaweed).
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Potato + buttertop 13% of all pairsSmell alikemoderateCooked together6,456 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
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Onion + buttertop 15% of all pairsSmell alikemoderateCooked together42,912 recipes
Shared aroma: decanal (soap, orange peel).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Potatoes
- Form the main body of the dish and brown on the outside when fried in butter.
- Onion
- Adds sweetness and savoury depth as it softens and browns in the butter.
- Butter
- Carries the frying and adds richness and browning to the potatoes and onion.
The step that matters
Fry the potatoes until light brown, turning often. Cold boiled potatoes firm up as they chill, so they hold their shape. Turning them often lets every side meet the hot fat and brown evenly, rather than scorching in spots or breaking apart.
Swap the parsley
How well each one fits the dish's main ingredients (potato, onion, butter):
- Garlicfits better
- Thymefits about as well
- Parsleythe original
- Capersfits less well
Fit is the average pairing score against potato, onion, butter. 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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