Skip to main content
Sauce

Spanish or Portugal Onion Sauce

A roasted onion sauce flavored with red Port, powdered sugar, lemon juice, salt, cayenne pepper, and butter.

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

Why it works: Lemon and pepper match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and 27,047 recipes mention both. Both carry trans-2-nonenal, which smells cardboard, fatty. The science ↓

Spanish or Portugal Onion Sauce

Ingredients

Directions

Roast and prepare

  1. Roast the onions until they are slightly more than half done.

  2. Peel the onions and add them to a pot with thickened gravy or coulis.

Season and cook

  1. Season with salt and Cayenne pepper.

  2. Add the red Port, powdered sugar, and lemon juice.

  3. Boil until the onions are tender, then mash with a little butter.

Serve

  1. Serve as a sauce for your preferred dish.

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 aroma chemistry they share, and how many recipes mention both.

  1. Lemon + peppertop 3% of all pairs
    Aroma overlapstrong
    Mentioned together27,047 recipes

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

  2. Onion + peppertop 11% of all pairs
    Aroma overlapmoderate
    Mentioned together68,474 recipes

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

  3. Onion + buttertop 15% of all pairs
    Aroma overlapmoderate
    Mentioned together42,912 recipes

    Shared aroma: decanal (soap, orange peel).

  4. Lemon + buttertop 16% of all pairs
    Aroma overlapmoderate
    Mentioned together41,227 recipes

    Shared aroma: 3-hexenal (apple, fruity).

  5. Sugar + buttertop 17% of all pairs
    Aroma overlapmoderate
    Mentioned 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

Spanish onions
Provide the main bulk and sweet flavour that the sauce is built around.
Red port
Adds depth, sweetness and fruity aroma while the liquid reduces.
Powdered loaf sugar
Adds sweetness that balances the sharpness of the wine and lemon.
Lemon juice
Adds acidity that brightens the sauce and balances the sweetness.
Thickened gravy or coulis
Supplies the liquid base and body that the softened onions are cooked in.

The step that matters

Boil until the onions are tender, then mash with a little butter. If the onions are not fully tender, the sauce stays grainy; boiling too hard can reduce the liquid too far or scorch the sugar, so a gentle simmer is safer. Butter added while mashing gives the sauce a smoother, rounder mouthfeel.

Flavor stand-ins for the lemon

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

  1. Lemonthe original
  2. Mangoabout as good a flavor fit

Fit is the average pairing score against onion, sugar, pepper, butter. Candidates are from the same food group and used in at least 100 recipes. This compares flavor only: it does not check the job the ingredient does in the dish (bulk, moisture, acidity, structure).

“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

Hot Lemon Cream SauceHot Lemon Cream Sauce11 recipesWine Sauce (for stewed fruit)Wine Sauce (for stewed fruit)186 recipesCaper SauceCaper Sauce180 recipesBrown SauceBrown Sauce141 recipes