Name: Boiled or Fried Onions
Ingredients: Onions; Salt; Butter; Pepper; Milk (optional)

Why it works: Butter and milk are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 81,283 recipes. Both carry (z)-4-heptenal, which smells biscuit, cream. The science ↓

Boiled or Fried Onions

Oven, in the book's wordsA moderate oven

Ingredients

Directions

Wash and peel the onions.
Boil in water for 10 minutes, then drain.
Add boiling water, salt, and boil for 1 hour.
Drain in a colander, press with a saucer to remove excess water.
Add butter and pepper to the drained onions.
For a creamier flavor, add 1 cup of milk to the boiling water 30 minutes before they are done.
To fry, slice the onions and boil for 10 minutes in three changes of water, then drain.
Fry in butter or beef drippings, stirring often, and season before serving hot.

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.

Butter + milktop 7% of all pairs

Smell alikemoderate

Cooked together81,283 recipes

Shared aroma: (z)-4-heptenal (biscuit, cream).
Onion + peppertop 11% of all pairs

Smell alikemoderate

Cooked together68,474 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Onion + buttertop 15% of all pairs

Smell alikemoderate

Cooked together42,912 recipes

Shared aroma: decanal (soap, orange peel).
Onion + milktop 20% of all pairs

Smell alikemoderate

Cooked together13,418 recipes

Shared aroma: hexanal (green, grassy).
Butter + peppertop 21% of all pairs

Smell alikemoderate

Cooked together85,593 recipes

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