Name: Mushroom Catsup
Ingredients: large flap mushrooms; coarse sea salt; ½ ounce black pepper; 40-50 cloves; 1 tablespoon brandy per pint; ⅓ cup claret (optional, per pint)

Why it works: Pepper and clove match in chemistry and in kitchens. They rank in the top 5% of all ingredient pairs, and cooks put them together in 17,451 recipes. Both carry ethyl octanoate, which smells fruity, wine. The science ↓

Mushroom Catsup

Ingredients

Directions

Salt the mushrooms

Clean the mushrooms.
Layer the mushrooms in a deep dish, sprinkling each layer with coarse sea salt. Continue layering until the dish is full.
Let the layered mushrooms sit for 8–12 hours.
Mash the mushrooms.
Strain off the juice.

Cook the ketchup

For each pint of juice, add ½ ounce of black pepper and 40–50 cloves.
Pour the mixture into a stone jar.
Place the jar in a saucepan of water.
Boil until about one‑third to one‑half has evaporated.
Let the mixture cool and settle.

Bottle

Strain the cooled mixture into pint or half‑pint bottles.
Add 1 tablespoon of brandy to each pint.
Optionally, add ⅓ cup of claret.

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.

Pepper + clovetop 5% of all pairs

Smell alikestrong

Cooked together17,451 recipes

Shared aroma: ethyl octanoate (fruity, wine).
Mushroom + clovetop 10% of all pairs

Smell alikemoderate

Cooked together2,663 recipes

Shared aroma: alpha-pinene (pine, turpentine).
Mushroom + peppertop 11% of all pairs

Smell alikemoderate

Cooked together13,580 recipes

Shared aroma: 2-nonenal (fatty, green).
Mushroom + brandytop 13% of all pairs

Smell alikemoderate

Cooked together206 recipes

Shared aroma: guaiacol (smoky, sweet).
Clove + brandytop 14% of all pairs

Smell alikemoderate

Cooked together2,362 recipes

Shared aroma: ethyl cinnamate (sweet, balsamic).

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

What each ingredient does

Large flap mushrooms: Provide the bulk of the juice that becomes the ketchup.
Coarse sea salt: Draws moisture out of the mushrooms and preserves the juice through the long rest.
Black pepper: Adds sharp, spicy aroma and flavour to the reduced juice.
Cloves: Add warm, aromatic spice that deepens the flavour of the ketchup.
Brandy: Adds alcohol that helps preserve the finished ketchup and adds aroma.

The step that matters

Boil until about one‑third to one‑half has evaporated. Evaporation concentrates the flavour and thickens the liquid. Stopping too early leaves the ketchup thin and less stable in storage, while boiling too long makes it overly dark and intense.