Why it works: Onion and pork are a kitchen classic. They rank in the top 10% of all ingredient pairs, and cooks put them together in 18,214 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Onion Soup
Ingredients
Directions
Prepare the base
Cut the pork into thin slices and fry slowly in a soup kettle.
Once thoroughly fried, add the sliced onions and fry slowly until golden brown, about 30 minutes.
Stir in the flour and cook for 10 more minutes, being careful not to let the onions turn dark brown.
Simmer and finish
Add 1 quart of boiling water and simmer gently for 2 hours (1 hour if short on time).
Add salt, pepper, and milk, then let the soup boil once.
Strain the soup and add the cracker crumbs.
Boil for 3 minutes and serve.
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 + porktop 10% of all pairsSmell alikemoderateCooked together18,214 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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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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Milk + porktop 12% of all pairsSmell alikemoderateCooked together4,386 recipes
Shared aroma: 4-heptenal (creamy, biscuit).
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Milk + flourtop 14% of all pairsSmell alikelowCooked together78,219 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Pork + peppertop 16% of all pairsSmell alikemoderateCooked together22,121 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Milk and flour barely smell alike, yet cooks put them together in 78,219 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 body and sweet, deep flavor as they brown slowly.
- Flour
- Thickens the soup as it cooks with the fat and onions.
- Milk
- Adds richness and a creamy body to the finished soup.
- Cracker crumbs
- Add final body and thickening to the strained soup.
- Fat salt pork
- Renders fat for frying the onions and adds savory, meaty flavor.
The step that matters
Browning the onions. Onions should turn golden brown, not dark brown. Scorched onions taste bitter and can spoil the whole soup, so keep the heat gentle and stir often.
Swap the onion
How well each one fits the dish's main ingredients (milk, flour, pork, pepper):
- Potatofits better
- Capsicumfits better
- Asparagusfits better
- Onionthe original
Fit is the average pairing score against milk, flour, pork, pepper. 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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