Skip to main content
Main

Onion Soup

A simple soup made with sliced onions, butter, water, and seasonings, finished with optional grated cheese.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 8 ingredients
Jump to recipe ↓

Why it works: Butter and cheese are a kitchen classic. They rank in the top 8% of all ingredient pairs, and cooks put them together in 7,962 recipes. Both carry delta-dodecalactone, which smells sweet, creamy. The science ↓

Onion Soup

Ingredients

Directions

The book gives no cooking times; the times in the steps were added in transcription, so check for doneness rather than trusting the clock.

Prepare

  1. Slice the onions thinly.

Make the soup

  1. In a pot, melt the butter over medium heat and add the onions.

  2. Cook until the onions are soft and golden, about 10 minutes.

  3. Stir in the flour and cook for 1 minute.

  4. Add water, salt, pepper, and bay leaf; bring to a boil.

  5. Reduce heat and simmer for 30 minutes.

  6. Remove bay leaf and serve hot, topped with cheese if desired.

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 + cheesetop 8% of all pairs
    Smell alikemoderate
    Cooked together7,962 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. Butter + flourtop 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. Onion + cheesetop 16% of all pairs
    Smell alikemoderate
    Cooked together4,849 recipes

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

Butter and flour 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
Soften and turn golden, building sweetness and savory depth as the soup base.
Butter
Carries the onions and adds richness and browning for flavor.
Flour
Thickens the cooking liquid slightly as it is stirred into the onions and butter.

The step that matters

Cooking the onions until soft and golden. Browning the onions slowly develops sweetness and deep flavor through caramelization. Rushing over high heat can scorch them, leaving a bitter taste that carries into the whole soup.

Swap the onion

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

  1. Capsicumfits better
  2. Mustardfits better
  3. Potatofits better
  4. Onionthe original

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

Macaroni and CheeseMacaroni and Cheese102 recipesCheese MakingCheese Making50 recipesCheese FrittersCheese Fritters34 recipesCheese OmeletteCheese Omelette31 recipes