Name: Bombay Onions Stuffed with Kidneys
Ingredients: 6 large Bombay onions; 10 sheep's kidneys, scalded and skinned; 2 anchovies; minced parsley; 1 lime; butter; spiced pepper

Why it works: Lime and pepper match in chemistry and in kitchens. They rank in the top 2% of all ingredient pairs, and cooks put them together in 3,491 recipes. Both carry beta-phellandrene, which smells minty, terpene. The science ↓

Bombay Onions Stuffed with Kidneys

Ingredients

Directions

Prepare the onions

Boil the onions until three‑quarters cooked, then drain.
Slice off the top of each onion and remove the inside, leaving a hollow space.

Prepare the filling

Cut the kidneys into eight pieces and prepare the anchovies by removing the spines and cutting them into small squares.

Stuff and bake

In each onion, place a lump of butter, some minced parsley, kidney pieces, and bits of anchovy.
Crown with minced parsley, a pat of butter, a drop of lime juice, and a dust of spiced pepper.
Replace the tops of the onions, place them in a buttered baking dish, and bake until fully cooked.

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.

Lime + peppertop 2% of all pairs

Smell alikestrong

Cooked together3,491 recipes

Shared aroma: beta-phellandrene (minty, terpene).
Parsley + limetop 2% of all pairs

Smell alikestrong

Cooked together547 recipes

Shared aroma: beta-phellandrene (minty, terpene).
Parsley + peppertop 2% of all pairs

Smell alikestrong

Cooked together34,122 recipes

Shared aroma: 4'-methylacetophenone (bitter almond).
Onion + parsleytop 9% of all pairs

Smell alikemoderate

Cooked together25,843 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).

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

What each ingredient does

Sheep's kidneys: Provide the rich, meaty filling that forms the main body of the dish.
Anchovies: Add a salty, savory depth that seasons the kidneys and onion filling.
Butter: Adds richness and moisture, helping the filling and onion stay tender while baking.
Bombay onions: Act as the edible vessel, softening and sweetening as they bake around the filling.

The step that matters

Boil the onions until three‑quarters cooked. Boiling only partly softens the onions so they hold their shape when hollowed and stuffed. Over-boiling makes the shells fragile and prone to tearing, while under-boiling leaves them firm and slow to cook through in the oven.