Name: Onion Preparation
Ingredients: small white onions; broth or stock; butter; flour; pepper; coarse sea salt; sugar; oil; cold boiled potatoes (optional)

Why it works: Onion and potato are a kitchen classic. They rank in the top 3% of all ingredient pairs, and cooks put them together in 9,023 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Onion Preparation

Ingredients

Directions

Cut off the ends of the small white onions.
Boil the onions in plenty of water for 15 minutes.
Transfer the onions to cold water, then remove the skin and first coating.
Stew the onions in broth or stock until tender.
Thicken the stock with butter and flour, and season with pepper, salt, and sugar.
Serve the onions with any dish or as a salad with oil and optional sliced cold boiled potatoes.

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 + potatotop 3% of all pairs

Smell alikemoderate

Cooked together9,023 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Pepper + potatotop 9% of all pairs

Smell alikemoderate

Cooked together8,305 recipes

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

Smell alikemoderate

Cooked together68,474 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Butter + flourtop 12% of all pairs

Smell alikelow

Cooked together124,287 recipes

Shared aroma: isobutyraldehyde (malty, green).
Butter + potatotop 13% of all pairs

Smell alikemoderate

Cooked together6,456 recipes

Shared aroma: (z)-4-heptenal (biscuit, cream).

Butter and flour barely smell alike, yet cooks put them together in 124,287 recipes: they work on texture and structure more than aroma.

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

Swap the potato

The recipe marks potato as optional. How well each one fits the dish's main ingredients (onion, butter, flour, pepper, sugar):

Chivefits about as well
Leekfits about as well
Okrafits about as well
Potatothe original

Fit is the average pairing score against onion, butter, flour, pepper, sugar. Candidates are from the same food group and used in at least 100 recipes.