Skip to main content
Main

Onion Soup

A savory soup made with sliced onions, butter, sugar, broth, bread, and Cognac brandy.

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

Why it works: Butter and bread are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 27,232 recipes. Both carry delta-decalactone, which smells sweet, creamy. The science ↓

Onion Soup

Ingredients

Directions

Caramelize the onions

  1. In a stew-pan, melt the butter over medium heat.

  2. Add the sliced onions and sugar, cooking until they turn golden brown.

Simmer and finish

  1. Pour in the broth and add the bread.

  2. Simmer for a few minutes until heated through.

  3. Before serving, stir in the Cognac brandy.

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

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

  2. Butter + cognac brandytop 13% of all pairs
    Smell alikemoderate
    Cooked together162 recipes

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

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

    Shared aroma: decanal (soap, orange peel).

  4. Onion + breadtop 15% of all pairs
    Smell alikemoderate
    Cooked together8,676 recipes

    Shared aroma: 2,4-decadienal (seaweed).

  5. Butter + sugartop 17% of all pairs
    Smell alikemoderate
    Cooked together98,233 recipes

    Shared aroma: guaiacol (smoky, sweet).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

What each ingredient does

Onions
Break down slowly into sweet, deeply flavoured body as they brown.
Butter
Carries fat for cooking the onions and adds rich, savoury flavour.
Sugar
Helps the onions brown and adds a touch of sweetness.
Broth
Provides the liquid base and moisture for the soup.
Bread
Soaks up broth and helps give the soup a thicker, heartier texture.
Cognac brandy
Adds a warm, aromatic finish when stirred in at the end.

The step that matters

Cooking the onions until golden brown. Onions must brown slowly over medium heat. Pale onions give a flat, raw taste, while scorched ones turn bitter. The browning reactions create the soup's depth of flavour and sweetness.

Swap the onion

How well each one fits the dish's main ingredients (butter, sugar, bread, cognac brandy):

  1. Shallotfits better
  2. Capsicumfits better
  3. Tomatofits about as well
  4. Onionthe original

Fit is the average pairing score against butter, sugar, bread, cognac brandy. 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 recipesWhite BreadWhite Bread80 recipesBread OmeletteBread Omelette60 recipesOatmeal BreadOatmeal Bread51 recipes