Name: Pickled Onion
Ingredients: small button onions; strong boiling hot brine; cold vinegar; whole pepper; bruised garlic; blades of mace; sliced horseradish

Why it works: Onion and garlic match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 29,058 recipes. Both carry furaneol, which smells caramel, strawberry. The science ↓

Pickled Onion

Ingredients

Directions

Choose small button onions of similar size and peel them.
Pour strong boiling hot brine over the onions and cover them closely.
The next day, drain the onions from the brine and wipe them dry.
Place the onions into cold vinegar along with whole pepper, bruised garlic, blades of mace, and sliced horseradish.
Keep the onions covered with vinegar, close the jar tightly, and set it in a cool, dry place.

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 + garlictop 1% of all pairs

Smell alikestrong

Cooked together29,058 recipes

Shared aroma: furaneol (caramel, strawberry).
Garlic + horseradishtop 5% of all pairs

Smell alikestrong

Cooked together719 recipes

Shared aroma: coumarin (sweet, hay).
Onion + horseradishtop 7% of all pairs

Smell alikestrong

Cooked together1,784 recipes

Shared aroma: coumarin (sweet, hay).
Pepper + garlictop 8% of all pairs

Smell alikemoderate

Cooked together27,090 recipes

Shared aroma: beta-phellandrene (minty, terpene).
Pepper + horseradishtop 11% of all pairs

Smell alikemoderate

Cooked together2,646 recipes

Shared aroma: coumarin (sweet, hay).

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

Swap the mace

How well each one fits the dish's main ingredients (onion, vinegar, pepper, garlic, horseradish):

Parsleyfits better
Tarragonfits better
Capersfits better
Macethe original

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