Why it works: Onion and pepper are a kitchen classic. They rank in the top 11% of all ingredient pairs, and cooks put them together in 68,474 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Onion Soup
Ingredients
Directions
Brown the onions
Fry and brown eight sliced onions in butter with a tablespoon of flour.
Put the mixture in a tin pail.
Make the soup
Stir in slowly four or five pints boiling milk (or part water).
Set the tin pail in a kettle of boiling water.
Season with salt and pepper.
Add a tea-cup of grated potato.
Cook from five to ten minutes.
Add a tea-cup of sweet cream.
Serve
Serve immediately.
Nutrition, whole recipe (rough)
What these numbers assume: 4 portions
| Ingredient | Portion assumed | kcal |
|---|---|---|
| Milk | 1 cup (244ml) whole | 149 |
| Onion | 1 medium (110g) | 44 |
| Black Pepper | 1 tsp ground (2.3g) | 6 |
| Salt | 1 tsp (6g) | 0 |
One typical portion per ingredient; the recipe's quantities are not counted. A rough guide only, not for medical or dietary planning.
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. See the original page.
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.
-
Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Milk + oniontop 20% of all pairsSmell alikemoderateCooked together13,418 recipes
Shared aroma: hexanal (green, grassy).
-
Milk + peppertop 22% of all pairsSmell alikemoderateCooked together26,984 recipes
Shared aroma: ethyl 2-methylbutyrate (fruity, apple).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Onions
- Browning in butter builds sweetness and savory depth as the soup's main flavor.
- Flour (in the method)
- Thickens the browned onions and butter so the milk later becomes a smooth, body-rich soup.
- Milk
- Forms the liquid base of the soup and gives it a creamy, mellow character.
- Potato (in the method)
- Grated potato releases starch that helps thicken the soup and adds body.
- Sweet cream (in the method)
- Added at the end, it adds richness and a silky texture.
The step that matters
Stir in the boiling milk slowly. Flour-thickened mixtures can form lumps when a hot liquid is added too fast. Adding the milk gradually while stirring lets the flour disperse evenly and keeps the soup smooth.
Swap the onion
How well each one fits the dish's main ingredients (milk, pepper):
- Capsicumfits better
- Potatofits better
- Tomatofits better
- Onionthe original
Fit is the average pairing score against milk, 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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