Why it works: Onion and butter are a kitchen classic. They rank in the top 15% of all ingredient pairs, and cooks put them together in 42,912 recipes. Both carry decanal, which smells soap, orange peel. The science ↓
Onions
Ingredients
Directions
Boil
Boil the onions in plenty of water with a little coarse sea salt.
After 30 minutes, drain the first water and add fresh water.
Let the onions boil slowly for 3 hours until tender.
Finish with butter
Drain the water and add a small piece of butter to the saucepan.
Toss the onions in the butter over the fire for 5 minutes.
Serve with or without the butter, based on preference.
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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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
- Onions
- Long simmering softens their dense layers until they become tender and easy to eat.
- Butter
- Adds richness and a glossy coating as the onions are tossed in it over heat.
The step that matters
Let the onions boil slowly for 3 hours until tender.. A gentle, slow boil softens the onions evenly without breaking them apart. A hard, rolling boil can make the outer layers break up before the centre becomes tender.
“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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