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
The book gives no oven temperature. The 400°F (200°C) in the steps was added when the recipe was transcribed, as a starting point.
Prepare
Slice the potatoes and chop the onion finely.
Assemble and bake
Layer the sliced potatoes in a baking dish, sprinkling with onion, salt, and pepper between layers.
Top with bread crumbs and dot with butter.
Pour the milk over the dish and bake at 400°F (200°C) until golden.
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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Bread + buttertop 7% of all pairsSmell alikemoderateCooked together27,232 recipes
Shared aroma: delta-decalactone (sweet, creamy).
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Milk + buttertop 7% of all pairsSmell alikemoderateCooked together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
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Potato + peppertop 9% of all pairsSmell alikemoderateCooked together8,305 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Potato + milktop 9% of all pairsSmell alikemoderateCooked together3,611 recipes
Shared aroma: (e,z)-2,6-nonadienal (cucumber, melon).
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, with soft, starchy layers that soak up the milk.
- Onion
- Adds a sharp, sweet aroma that mellows during baking.
- Milk
- Provides moisture that soaks into the potatoes and helps create a creamy texture.
- Butter
- Adds fat and richness, and helps the top brown.
- Bread crumbs
- Form a crisp layer that browns on top.
The step that matters
Baking until golden. The milk needs time to soak through the layers and the potatoes need to soften fully. The golden top comes from browning of the milk solids and butter, so bake until the top is evenly golden.
Swap the onion
How well each one fits the dish's main ingredients (potato, pepper, milk, bread, butter):
- Capsicumfits better
- Tomatofits better
- Asparagusfits about as well
- Onionthe original
Fit is the average pairing score against potato, pepper, milk, bread, 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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