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 ↓
Potatoes Au Gratin
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.
Make the sauce
In another saucepan, melt the butter over medium heat until bubbling.
Add the flour, salt, and pepper, stirring until blended.
Gradually pour in the milk, stirring well after each addition until smooth and glossy.
Assemble and bake
Reheat the diced potatoes in a saucepan with the white sauce.
Transfer the mixture to a buttered baking dish, cover with buttered crumbs, and bake at 400°F (200°C) until the crumbs are brown.
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.
Photo for illustrative purposes only · Contact us to use it
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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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).
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Potato + buttertop 13% of all pairsSmell alikemoderateCooked together6,456 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
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
- Potatoes
- Form the bulk of the dish, staying soft inside while the topping browns.
- White sauce
- Provides moisture and a creamy, binding texture that coats the potatoes.
- Butter
- Adds richness and fat, and helps the crumbs brown in the oven.
- All-purpose flour
- Thickens the butter and milk into a smooth, stable sauce.
- Milk
- Adds liquid and body to the sauce, setting it into a smooth, glossy texture.
The step that matters
Adding the milk gradually. Pouring milk in slowly while stirring keeps the flour mixture smooth; adding it all at once can trap lumps that do not dissolve easily.
Swap the potato
How well each one fits the dish's main ingredients (sauce, butter, flour, pepper, milk):
- Capsicumfits about as well
- Shallotfits about as well
- Potatothe original
- Chivefits about as well
Fit is the average pairing score against sauce, butter, flour, pepper, 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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