Skip to main content
Main

Brown Onion Soup

A soup made from sliced onions, butter, water, and seasoned with salt, pepper, and vinegar, finished with egg yolks.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 7 ingredients
Jump to recipe ↓

Why it works: Onion and pepper are a kitchen classic. They rank in the top 11% of all ingredient pairs, and cooks put them together in 68,474 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Brown Onion Soup

Ingredients

Directions

Prepare the onions

  1. Peel and slice the onions into thin rings.

  2. Fry the onions in butter until tender and brown.

  3. Drain the onions on a sieve to remove excess butter.

Make the soup

  1. In a kettle, combine the onions with 5 quarts of water and boil for 1 hour, stirring often.

  2. Season with salt and pepper to taste.

  3. Rub the crumbs through a colander and add to the soup, stirring continuously to keep it smooth.

  4. Boil for an additional 2 hours.

Finish and serve

  1. Ten minutes before serving, beat the egg yolks with vinegar and a little soup.

  2. Gradually pour the egg mixture into the soup while stirring continuously.

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

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

  2. Onion + vinegartop 14% of all pairs
    Smell alikemoderate
    Cooked together18,226 recipes

    Shared aroma: acetic acid (sour, vinegar).

  3. Pepper + vinegartop 14% of all pairs
    Smell alikemoderate
    Cooked together27,814 recipes

    Shared aroma: 4'-methylacetophenone (bitter almond).

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

    Shared aroma: decanal (soap, orange peel).

  5. Pepper + teatop 15% of all pairs
    Smell alikemoderate
    Cooked together260 recipes

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

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

What each ingredient does

Spanish onions
Provide the main body and sweet, deep flavour of the soup after long cooking.
Butter
Fries the onions until they brown, adding richness and flavour.
Roll or tea biscuit crumbs
Thicken the soup as they break down into the liquid.
Egg yolks
Enrich and thicken the soup when gently stirred in at the end.
Vinegar
Adds a touch of acidity that brightens the rich onion flavour.

The step that matters

Adding the egg yolk mixture. Egg yolks can curdle or scramble if they meet very hot liquid too quickly. Mixing them with vinegar and a little soup first, then pouring slowly while stirring, tempers the eggs so they thicken the soup smoothly.

Swap the onion

How well each one fits the dish's main ingredients (butter, pepper, tea, egg, vinegar):

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

Fit is the average pairing score against butter, pepper, tea, egg, vinegar. 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.

You might also like

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