Why it works: Butter and bread are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 27,232 recipes. Both carry delta-decalactone, which smells sweet, creamy. The science ↓
Onion Soup
Ingredients
Directions
The book gives no cooking times; the times in the steps were added in transcription, so check for doneness rather than trusting the clock.
Prepare
Peel and slice the onions.
Make the soup
In a pot, melt butter and sauté the onions until golden.
Add water and bring to a boil.
Season with salt and pepper.
Simmer for 30 minutes.
Serve
Serve hot with toasted bread and grated cheese on top.
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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Butter + breadtop 7% of all pairsSmell alikemoderateCooked together27,232 recipes
Shared aroma: delta-decalactone (sweet, creamy).
-
Bread + cheesetop 7% of all pairsSmell alikemoderateCooked together2,130 recipes
Shared aroma: delta-decalactone (sweet, creamy).
-
Butter + cheesetop 8% of all pairsSmell alikemoderateCooked together7,962 recipes
Shared aroma: delta-dodecalactone (sweet, creamy).
-
Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
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
- Provide the main body of the soup and sweetness as they caramelise during sautéing.
- Butter
- Adds fat for sautéing and helps the onions brown and develop flavour.
- Bread
- Soaks up broth and adds texture when toasted and served with the soup.
- Cheese
- Melts over the top, adding richness and savoury flavour.
The step that matters
Sautéing the onions until golden. Onions must brown slowly so their sugars caramelise and develop deep flavour. Cooking them too quickly over high heat can scorch them and leave a bitter taste.
Swap the onion
How well each one fits the dish's main ingredients (butter, pepper, bread, cheese):
- Capsicumfits better
- Tomatofits better
- Potatofits about as well
- Onionthe original
Fit is the average pairing score against butter, pepper, bread, 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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