Name: Caramelized Sweet and Sour Onion Marmalade
Yield: 2 cups
Ingredients: 4 tablespoons olive or vegetable oil; 4 large yellow or white onions , sliced into thin strips; ½ cups white granulated sugar; ¼ cup balsamic vinegar; ¼ teaspoon salt; ⅛ teaspoon coarse ground black pepper

Why it works: Olive and onion are a kitchen classic. They rank in the top 8% of all ingredient pairs, and cooks put them together in 29,779 recipes. Both carry 2,4-decadienal, which smells seaweed. The science ↓

Caramelized Sweet and Sour Onion Marmalade

2 cups

Timeabout 15 minutes

Ingredients

4 tablespoons olive or vegetable oil
4 large yellow or white onions , sliced into thin strips
½ cups white granulated sugar
¼ cup balsamic vinegar
¼ teaspoon salt
⅛ teaspoon coarse ground black pepper

Directions

Make the onions

Heat oil in a large frying pan over medium heat.
Add onions, and sauté, stirring, for about 15 minutes, or until they begin to brown. Do not cook over high heat, as the outside of the onions will char too quickly before the insides have softened and sweetened.
When onions have softened and turned a light golden brown, add sugar. Continue stirring until sugar melts and begins to bubble.

Glaze and finish

As the onions turn a richer brown, clear a space in the center of the pan. Pour balsamic vinegar directly onto the hot pan, then stir it into onions.
When vinegar has reduced, leaving a syrupy coating on the onions, turn off the heat.
Stir in salt and pepper, and allow onions to cool.

Nutrition, whole recipe (rough)

225Calories

1 gProtein

14 gFat

24 gCarbs

What these numbers assume: 7 portions

Ingredient	Portion assumed	kcal
Olive Oil	1 tbsp (14g)	119
Sugar	1 tbsp (12.5g) granulated	49
Onion	1 medium (110g)	44
Black Pepper	1 tsp ground (2.3g)	6
Olive	1 large (4g)	4
Vinegar	1 tbsp (15ml) distilled	3
Salt	1 tsp (6g)	0

One typical portion per ingredient; the recipe's quantities are not counted. A rough guide only, not for medical or dietary planning.

Recipe from the Wikibooks Cookbook.

Steps grouped into stages for easier reading; the method is the source's own.

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.

Olive + oniontop 8% of all pairs

Smell alikemoderate

Cooked together29,779 recipes

Shared aroma: 2,4-decadienal (seaweed).
Olive + vinegartop 10% of all pairs

Smell alikemoderate

Cooked together12,297 recipes

Shared aroma: isoamyl acetate (banana, fruity).
Onion + peppertop 11% of all pairs

Smell alikemoderate

Cooked together68,474 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Olive + peppertop 11% of all pairs

Smell alikemoderate

Cooked together30,263 recipes

Shared aroma: 2,4-decadienal (seaweed).
Onion + vinegartop 14% of all pairs

Smell alikemoderate

Cooked together18,226 recipes

Shared aroma: acetic acid (sour, vinegar).

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

What each ingredient does

Onions: Soften and slowly brown, becoming sweet and forming the jam-like body of the marmalade.
Sugar: Caramelizes with the onions, adding sweetness and deeper brown flavor.
Balsamic vinegar: Adds acidity and reduces to a syrupy coating that balances the sweetness.
Olive or vegetable oil: Conducts heat and helps the onions soften and brown evenly in the pan.

The step that matters

Keep the heat at medium. High heat scorches the outside of the onions before the inside softens and sweetens. Gentle heat lets the sugars in the onions develop slowly into even browning and rich flavor.

Swap the onion

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

Capsicumfits better
Mustardfits better
Tomatofits better
Onionthe original

Fit is the average pairing score against olive, sugar, vinegar, pepper. 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.

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Caramelized Sweet and Sour Onion Marmalade