Why it works: Butter and cream are a kitchen classic. They rank in the top 8% of all ingredient pairs, and cooks put them together in 41,516 recipes. Both carry delta-dodecalactone, which smells sweet, creamy. The science ↓
Onion Soup
Ingredients
Directions
Make the soup base
Melt the butter in a pot and stir in the chopped onions until they begin to brown.
Add the water and cook until the water evaporates and the onions brown further.
Pour in the cream stock and season to taste.
Finish and serve
In a bowl, mix the egg yolks with the cream.
Cook the mixture for five minutes, then strain it.
Serve the soup hot with croutons.
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 + creamtop 8% of all pairsSmell alikemoderateCooked together41,516 recipes
Shared aroma: delta-dodecalactone (sweet, creamy).
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Butter + oniontop 15% of all pairsSmell alikemoderateCooked together42,912 recipes
Shared aroma: decanal (soap, orange peel).
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Butter + eggtop 17% of all pairsSmell alikemoderateCooked together118,967 recipes
Shared aroma: decanal (soap, orange peel).
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Onion + creamtop 18% of all pairsSmell alikelowCooked together10,827 recipes
Shared aroma: 2-nonanone (fruity, floral).
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Cream + eggtop 24% of all pairsSmell alikelowCooked together42,166 recipes
Shared aroma: acetic acid (sour, vinegar).
Onion and cream barely smell alike, yet cooks put them together in 10,827 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
- Butter
- Adds fat and richness, and helps the onions brown in the pot.
- Onions
- Provide the base flavor, which deepens as the onions brown.
- Egg yolks
- Thicken the soup when gently cooked, giving it a smooth, rich body.
- Cream
- Adds richness and body, and softens the flavor of the soup.
- Cream stock
- Forms the liquid base of the soup and carries its savory flavor.
The step that matters
Cooking the egg yolk and cream mixture. Egg yolks thicken through gentle heat, but too much heat can scramble them. Keep the heat moderate and stir while cooking, then strain to remove any lumps.
Swap the onion
How well each one fits the dish's main ingredients (butter, cream, egg):
- Leekfits better
- Potatofits better
- Asparagusfits better
- Onionthe original
Fit is the average pairing score against butter, cream, egg. 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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