Skip to main content
Main

Onion Soup

A creamy onion soup made with butter, flour, and cream, seasoned with salt and pepper.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 6 ingredients
Jump to recipe ↓

Why it works: Cream and butter 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

Cook the onions

  1. Slice the onions and cook them in butter until light yellow.

  2. Cover and cook slowly for 30 minutes.

Thicken and finish

  1. Mix the flour with hot milk until smooth, then add to the onions.

  2. Bring to a boil and strain through a sieve.

  3. Return to heat, season with salt and pepper, and stir in the cream.

  4. Serve with croutons.

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. Cream + buttertop 8% of all pairs
    Smell alikemoderate
    Cooked together41,516 recipes

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

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

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

  3. Flour + buttertop 12% of all pairs
    Smell alikelow
    Cooked together124,287 recipes

    Shared aroma: isobutyraldehyde (malty, green).

  4. Onion + buttertop 15% of all pairs
    Smell alikemoderate
    Cooked together42,912 recipes

    Shared aroma: decanal (soap, orange peel).

  5. Flour + oniontop 17% of all pairs
    Smell alikemoderate
    Cooked together32,460 recipes

    Shared aroma: isobutyraldehyde (malty, green).

Flour and butter barely smell alike, yet cooks put them together in 124,287 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
Form the main body of the soup, becoming sweet and soft as they cook slowly in butter.
Flour
Thickens the liquid so the soup becomes smooth and body-rich rather than watery.
Cream
Adds richness and a silky mouthfeel when stirred in at the end.
Butter
Carries the onions' flavour and helps them brown gently during the initial cooking.

The step that matters

Mix the flour with hot milk until smooth. Flour clumps if added dry or to cold liquid. Whisking it into hot milk until smooth lets starch disperse evenly, so the soup thickens without lumps.

Swap the onion

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

  1. Spinachfits better
  2. Leekfits better
  3. Potatofits better
  4. Onionthe original

Fit is the average pairing score against cream, flour, pepper, butter. 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

Tomato SoupTomato Soup526 recipesBrown BreadBrown Bread461 recipesMutton BrothMutton Broth292 recipesYorkshire PuddingYorkshire Pudding264 recipes