Name: Romaine Sauce for Watercresses
Ingredients: ½ ounce onion, grated; 2 tablespoons vinegar; ¼ teaspoon sugar; 1 tablespoon lemon juice; 3 tablespoons olive oil; 6 capers, chopped; cayenne pepper, to taste; ¼ teaspoon salt; ⅛ teaspoon pepper

Why it works: Olive and capers match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 1,688 recipes. Both carry coumarin, which smells sweet, hay. The science ↓

Romaine Sauce for Watercresses

Ingredients

Directions

Make the dressing

Grate the onion and wash it off the grater with vinegar.
Add sugar, lemon juice, olive oil, chopped capers, cayenne pepper, salt, and pepper. Mix well and use as a dressing for watercresses or any green salad.

Serve

For a potato salad, mix sliced cold boiled potatoes and a head of lettuce with the dressing.

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.

Olive + caperstop 3% of all pairs

Smell alikestrong

Cooked together1,688 recipes

Shared aroma: coumarin (sweet, hay).
Lemon + peppertop 3% of all pairs

Smell alikestrong

Cooked together27,047 recipes

Shared aroma: trans-2-nonenal (cardboard, fatty).
Lemon + caperstop 5% of all pairs

Smell alikestrong

Cooked together1,222 recipes

Shared aroma: coumarin (sweet, hay).
Onion + caperstop 7% of all pairs

Smell alikestrong

Cooked together1,381 recipes

Shared aroma: coumarin (sweet, hay).
Lemon + olivetop 7% of all pairs

Smell alikemoderate

Cooked together11,922 recipes

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

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

What each ingredient does

Onion: Adds sharp aromatic flavour that blends into the dressing when finely grated.
Vinegar: Provides acidity that brightens the dressing and balances the oil.
Olive oil: Adds fat and body, carrying flavour and coating the leaves.
Lemon juice: Adds acidity and fresh citrus flavour to the dressing.
Capers: Add briny, sharp notes that give the dressing savoury punch.

Swap the onion

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

Mustardfits better
Shallotfits better
Kalefits better
Onionthe original

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