Name: Walnut Catsup
Ingredients: 100 young walnuts; 6 ounces fine anchovies; 4 ounces shallots; ½ ounce black pepper; ¼ ounce cloves; 1 teaspoon mace; vinegar (optional)

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 ↓

Walnut Catsup

Ingredients

Directions

Prepare

Pound the young walnuts in a mortar.

Make the ketchup

Boil the expressed juice of the walnuts for 1 hour.
Add the anchovies, shallots, black pepper, cloves, and mace to the juice.
If using vinegar, drain the walnuts and boil the vinegar with additional spices and shallots for a few minutes.

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).
Shallot + clovetop 5% of all pairs

Smell alikestrong

Cooked together1,677 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).
Walnut + shallottop 6% of all pairs

Smell alikestrong

Cooked together440 recipes

Shared aroma: 2,4-decadienal (seaweed).
Clove + macetop 6% of all pairs

Smell alikelow

Cooked together8,400 recipes

Shared aroma: methyleugenol (clove, spice).
Walnut + clovetop 9% of all pairs

Smell alikestrong

Cooked together1,592 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).

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

What each ingredient does

Young walnuts: Provide the juice and bulk that form the ketchup's base.
Anchovies: Add savory depth and umami, giving the ketchup its salty richness.
Shallots: Contribute aromatic sharpness and savory flavor as they cook down.
Black pepper: Adds pungent warmth and a sharp, spiced bite.

Swap the mace

How well each one fits the dish's main ingredients (walnut, shallot, pepper, clove, vinegar):

Tarragonfits better
Allspicefits better
Thymefits better
Macethe original

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

“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.