Why it works: Milk and butter are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 81,283 recipes. Both carry (z)-4-heptenal, which smells biscuit, cream. The science ↓
Onion Soup
Ingredients
Directions
Prepare the onions
Cut six white onions fine, and fry in a spoonful of butter till a light brown.
Make the soup
Add a quart of boiling water and one pint milk; season with 1 teaspoon salt, 1 saltspoon pepper, a pinch of mace and a teaspoon sugar.
Boil very slowly for an hour and then strain.
Thicken and serve
Beat 4 eggs to a foam, add one cup cream, and one tablespoon cornstarch dissolved in a little cold water.
Boil up once and serve with croutons.
Nutrition, whole recipe (rough)
Counts 8 of 10 ingredients. The other 2 aren't in our nutrition table and add nothing above, so the real totals are higher.
What these numbers assume: 8 portions
| Ingredient | Portion assumed | kcal |
|---|---|---|
| Flour | 1 cup (125g) all-purpose | 455 |
| Milk | 1 cup (244ml) whole | 149 |
| Butter | 1 tbsp (14g) | 102 |
| Egg | 1 large egg (50g) | 78 |
| Cream | 1 tbsp (15ml) heavy | 51 |
| Onion | 1 medium (110g) | 44 |
| Black Pepper | 1 tsp ground (2.3g) | 6 |
| Salt | 1 tsp (6g) | 0 |
| Water | not in our table | 0 |
| Mace | not in our table | 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.
-
Milk + buttertop 7% of all pairsSmell alikemoderateCooked together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
-
Cream + buttertop 8% of all pairsSmell alikemoderateCooked together41,516 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).
-
Butter + oniontop 15% of all pairsSmell alikemoderateCooked together42,912 recipes
Shared aroma: decanal (soap, orange peel).
-
Mace + peppertop 16% of all pairsSmell alikelowCooked together12,257 recipes
Shared aroma: myristicin (spice, warm).
Mace and pepper barely smell alike, yet cooks put them together in 12,257 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
- White onions
- Softened and lightly browned in butter, they add sweetness and the base flavour of the soup.
- Milk
- Forms the liquid body of the soup and carries the seasonings.
- Cream
- Adds richness and a smoother, fuller mouthfeel.
- Eggs
- Beaten eggs set when heated, adding body and richness to the soup.
- Cornstarch
- Thickens the soup as its starch swells and gelatinises when boiled.
The step that matters
Boil up once after adding the egg and cornstarch mixture. Cornstarch needs to reach a boil to thicken fully, but egg proteins can scramble and curdle if the soup is overheated or boiled hard, so the heat must be brief and controlled.
Swap the mace
How well each one fits the dish's main ingredients (milk, cream, butter, onion, pepper, egg):
- Nutmegfits better
- Parsleyfits better
- Garlicfits better
- Macethe original
Fit is the average pairing score against milk, cream, butter, onion, pepper, 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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