Name: Rice and Onions
Ingredients: whole onions; washed rice; ¼ teaspoon pepper; ¼ teaspoon coarse sea salt; 2 tablespoons butter

Why it works: Onion and rice are a kitchen classic. They rank in the top 9% of all ingredient pairs, and cooks put them together in 10,433 recipes. Both carry 2,4-decadienal, which smells seaweed. The science ↓

Rice and Onions

Ingredients

Directions

Cook the onions

Boil whole onions in water until fully cooked.
Remove the onions from the water.

Cook the rice

Add washed rice, pepper, salt, and butter to the onion water.
Cook the rice until done.

Serve

Serve the rice with the onions and a green vegetable.

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 + ricetop 9% of all pairs

Smell alikemoderate

Cooked together10,433 recipes

Shared aroma: 2,4-decadienal (seaweed).
Onion + peppertop 11% of all pairs

Smell alikemoderate

Cooked together68,474 recipes

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

Smell alikemoderate

Cooked together8,379 recipes

Shared aroma: trans-2-nonenal (cardboard, fatty).
Onion + buttertop 15% of all pairs

Smell alikemoderate

Cooked together42,912 recipes

Shared aroma: decanal (soap, orange peel).
Rice + buttertop 16% of all pairs

Smell alikemoderate

Cooked together9,645 recipes

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

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

What each ingredient does

Whole onions: Cook in the water to flavour it, then serve alongside the rice as the main vegetable.
Washed rice: Forms the body of the dish; it absorbs the onion-infused cooking water as it cooks.
Butter: Adds fat and richness, giving the rice a softer mouthfeel and a rounder flavour.