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 ↓
Scalloped Onions
Ingredients
Directions
The book gives no oven temperature. The 350°F (175°C) in the steps was added when the recipe was transcribed, as a starting point. The book gives no cooking times either; the times in the steps were added in transcription, so check for doneness rather than trusting the clock.
Make the sauce
Preheat the oven to 350°F (175°C).
Melt the butter in a pan and sauté the onions until soft.
Stir in the flour, salt, and pepper, cooking for a few minutes.
Gradually add the hot milk, stirring until thickened.
Assemble and bake
Layer the onions in a baking dish, pour the sauce over, and top with cheese if desired.
Bake for 30 minutes until golden 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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Butter + cheesetop 8% of all pairsSmell alikemoderateCooked together7,962 recipes
Shared aroma: delta-dodecalactone (sweet, creamy).
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Milk + cheesetop 10% of all pairsSmell alikemoderateCooked together4,426 recipes
Shared aroma: delta-dodecalactone (sweet, creamy).
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Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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
- Onions
- Provide the main bulk and sweet, soft flavor once cooked down in butter.
- Butter
- Adds fat for richness and helps soften the onions without browning them quickly.
- Flour
- Thickens the milk into a smooth sauce that holds the onions together.
- Hot milk
- Forms the creamy liquid base that thickens with the flour into a sauce.
- Cheese
- Melts and browns on top, adding savory flavor and a golden crust.
The step that matters
Gradually add the hot milk, stirring until thickened. Adding the milk slowly while stirring lets the flour disperse evenly. Adding it all at once can form lumps, leaving the sauce grainy instead of smooth.
Swap the onion
How well each one fits the dish's main ingredients (butter, milk, flour, pepper, cheese):
- Potatofits better
- Capsicumfits better
- Asparagusfits better
- Onionthe original
Fit is the average pairing score against butter, milk, flour, pepper, cheese. 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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