Skip to main content
Main

Onion Soup

A savory soup made from onions, butter, flour, stock, milk, and seasonings, served with fried bread.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 9 ingredients
Jump to recipe ↓

Why it works: Pepper and lemon match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 27,047 recipes. Both carry trans-2-nonenal, which smells cardboard, fatty. The science ↓

Onion Soup

Ingredients

Directions

Prepare the soup

  1. Peel and slice the onions.

  2. Fry the onions in the butter until they are a good brown color.

  3. Sprinkle the flour over the onions and brown it as well.

  4. Pour in the boiling stock and boil steadily until the onions are very soft.

Finish and serve

  1. Rub the mixture through a sieve.

  2. If there is any fat, remove it carefully.

  3. Pour the soup back into the saucepan, add the milk, salt, and pepper, and bring to a boil.

  4. Just before serving, add a few drops of lemon juice.

  5. Serve with fried bread.

Recipe from a historical cookbook (Internet Archive).

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.

  1. Pepper + lemontop 3% of all pairs
    Smell alikestrong
    Cooked together27,047 recipes

    Shared aroma: trans-2-nonenal (cardboard, fatty).

  2. Butter + breadtop 7% of all pairs
    Smell alikemoderate
    Cooked together27,232 recipes

    Shared aroma: delta-decalactone (sweet, creamy).

  3. Butter + milktop 7% of all pairs
    Smell alikemoderate
    Cooked together81,283 recipes

    Shared aroma: (z)-4-heptenal (biscuit, cream).

  4. Milk + breadtop 11% of all pairs
    Smell alikemoderate
    Cooked together11,466 recipes

    Shared aroma: 2-undecenal (sweet).

  5. Onion + peppertop 11% of all pairs
    Smell alikemoderate
    Cooked together68,474 recipes

    Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).

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 the soup's deep, sweet flavor and color.
Butter
Fat for frying the onions, carrying flavor and helping them brown.
Flour
Browned with the onions, it thickens the stock into a body-rich soup.
Stock
Liquid base that softens the onions and forms the soup.
Milk
Added at the end to mellow the flavor and enrich the texture.

The step that matters

Fry the onions until a good brown. Browning caramelizes the onions' sugars, which gives the soup its color and depth. Pale onions yield a flat, thin-tasting soup.

Swap the onion

How well each one fits the dish's main ingredients (butter, flour, milk, pepper, lemon, bread):

  1. Shallotfits better
  2. Asparagusfits better
  3. Capsicumfits better
  4. Onionthe original

Fit is the average pairing score against butter, flour, milk, pepper, lemon, bread. 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.

More onion soup recipes

French 31Brown 15with Milk 7White 5Bavarian 4Bermuda 4 See all 236 →

You might also like

Brown BreadBrown Bread461 recipesLemon SauceLemon Sauce236 recipesWhite BreadWhite Bread80 recipesBread OmeletteBread Omelette60 recipes