Name: Baked Onions
Ingredients: large onions; 1 teaspoon salt; melted butter; salt and pepper to taste

Why it works: Onion and pepper are a kitchen classic. They rank in the top 11% of all ingredient pairs, and cooks put them together in 68,474 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Baked Onions

Oven, in the book's wordsA very slow oven

Ingredients

large onions
1 teaspoon salt
melted butter
salt and pepper to taste

Directions

The book says “a very slow oven”. The 300°F (150°C) in the steps is the modern equivalent, not the book's own figure.

Trim the bottoms of the onions and remove one or two layers of the outer skin without peeling them completely.
Boil the onions in a kettle of water with 1 teaspoon of salt for about 1 hour.
Drain the onions in a colander and dry each one.
Wrap each onion in squares of tissue paper, twisting tightly at the top.
Place the wrapped onions in a baking pan and bake at 300°F (150°C) for 1 hour.
Remove the paper, peel the onions, and place them in a serving dish.
Pour melted butter over the onions and season with salt and pepper before serving.

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 + 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).
Butter + peppertop 21% of all pairs

Smell alikemoderate

Cooked together85,593 recipes

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