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
Boil, peel, and slice the potatoes.
Cook
Heat the butter in a frying pan and add the sliced onion.
Cook until the onion is slightly brown, then add the potatoes.
Season with salt and cook until the potatoes are golden brown.
Sprinkle the chopped parsley over the potatoes before serving.
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).
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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 bulk of the dish and turn golden and crisp as they fry in the pan.
- Onion
- Softens and browns, adding sweetness and savoury depth to the potatoes.
- Butter
- Conducts heat for frying and adds richness and browning to the potatoes and onion.
The step that matters
Cook until the potatoes are golden brown. Potatoes brown through the Maillard reaction and caramelisation when they are dry and hot enough. Crowding the pan or stirring too often traps moisture and steams them instead of browning them.
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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