Name: Romaine Salad Dressing
Ingredients: ½ ounce onion, grated; 1 teaspoon lemon juice; ¼ teaspoon salt; ¼ teaspoon powdered sugar; ¼ teaspoon white pepper; ¼ teaspoon dry mustard; 3 tablespoons oil; 1 tablespoon vinegar

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 ↓

Romaine Salad Dressing

Ingredients

Directions

Make the dressing

In a bowl, mix grated onion with lemon juice, salt, powdered sugar, white pepper, and dry mustard.
Gradually add oil and vinegar, stirring continuously until well combined.

Serve

Use for lettuce or tomato salad.

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.

Onion + mustardtop 6% of all pairs

Smell alikestrong

Cooked together9,259 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Mustard + vinegartop 7% of all pairs

Smell alikemoderate

Cooked together14,067 recipes

Shared aroma: isobutyraldehyde (malty, green).
Lemon + mustardtop 11% of all pairs

Smell alikestrong

Cooked together3,816 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).
Onion + vinegartop 14% of all pairs

Smell alikemoderate

Cooked together18,226 recipes

Shared aroma: acetic acid (sour, vinegar).
Sugar + vinegartop 15% of all pairs

Smell alikemoderate

Cooked together20,806 recipes

Shared aroma: beta-damascenone (apple, rose).

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

What each ingredient does

Oil: Forms the body of the dressing and carries flavor, giving it a smooth, rich mouthfeel.
Vinegar: Adds acidity that sharpens the flavor and balances the richness of the oil.
Grated onion: Contributes sharp aroma and pungent flavor to the dressing.
Lemon juice: Adds acidity and brightness to the dressing.
Powdered sugar: Adds a touch of sweetness that rounds out the sharpness of the acids.

The step that matters

Gradually add oil and vinegar while stirring. Oil and vinegar do not mix on their own. Adding them slowly while stirring breaks the oil into small droplets held in suspension, so the dressing stays combined rather than separating into layers.

Swap the white pepper

How well each one fits the dish's main ingredients (onion, lemon, sugar, mustard, vinegar):

Tarragonfits better
Capersfits better
Dillfits better
White pepperthe original

Fit is the average pairing score against onion, lemon, sugar, mustard, 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.

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Romaine Salad Dressing