Skip to main content
Sauce

Fried Onion Sauce

A sauce made from fried onions, butter, broth, mushroom ketchup, beer, peppercorns, salt, flour, and mustard.

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

Why it works: Onion and mustard match in chemistry and in kitchens. They rank in the top 6% of all ingredient pairs, and cooks put them together in 9,259 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Fried Onion Sauce

Ingredients

Directions

  1. Slice the onions and fry them in butter, turning often, until browned.

  2. Pour in the broth or water, mushroom ketchup, table beer, peppercorns, and salt.

  3. Add the flour, cover the saucepan, and let it simmer for 30 minutes until thickened.

  4. Press the sauce through a fine sieve and stir in the made mustard.

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 + mustardtop 6% of all pairs
    Smell alikestrong
    Cooked together9,259 recipes

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

  2. Butter + mushroomtop 7% of all pairs
    Smell alikemoderate
    Cooked together12,525 recipes

    Shared aroma: trans-2-decenal (waxy, orange).

  3. Onion + mushroomtop 10% of all pairs
    Smell alikemoderate
    Cooked together10,626 recipes

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

  4. Mushroom + beertop 10% of all pairs
    Smell alikemoderate
    Cooked together128 recipes

    Shared aroma: 1-octen-3-one (mushroom, metallic).

  5. Beer + mustardtop 11% of all pairs
    Smell alikemoderate
    Cooked together314 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
Browning in butter builds the sweet, savoury base flavour of the sauce.
Butter
Fat that fries the onions and carries flavour through the sauce.
Flour
Thickens the liquid as it simmers, giving the sauce body.
Broth or water
Forms the liquid base that the flour thickens into sauce.
Made mustard
Adds sharp, acidic bite that balances the sweetness of the onions.

The step that matters

Frying the onions until browned. Onions cooked slowly until deeply browned develop sweetness and savoury depth through caramelisation. Pale or under-browned onions leave the sauce flat, so turning them often helps them colour evenly without burning.

Swap the onion

How well each one fits the dish's main ingredients (butter, mushroom, ketchup, beer, flour, mustard):

  1. Shallotfits better
  2. Horseradishfits better
  3. Chivefits better
  4. Onionthe original

Fit is the average pairing score against butter, mushroom, ketchup, beer, flour, mustard. 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

Mixed MustardMixed Mustard9 recipesWine Sauce (for stewed fruit)Wine Sauce (for stewed fruit)186 recipesCaper SauceCaper Sauce180 recipesBrown SauceBrown Sauce141 recipes