Name: Nonpareil Sauce
Ingredients: 1 slice boiled ham; 1 slice roasted fowl breast; 1 pickled cucumber; 1 hard-boiled egg yolk; 1 anchovy; 1 tablespoon chopped parsley; 1 shallot, finely chopped; ½ cup good ketchup

Why it works: Parsley and shallot match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 3,737 recipes. Both carry 2,4-decadienal, which smells seaweed. The science ↓

Nonpareil Sauce

Ingredients

Directions

Chop the boiled ham, roasted fowl, pickled cucumber, hard-boiled egg yolk, anchovy, parsley, and shallot very finely.
Boil the mixture briefly in the ketchup.
Serve as a sauce for meat or fish.

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.

Parsley + shallottop 1% of all pairs

Smell alikestrong

Cooked together3,737 recipes

Shared aroma: 2,4-decadienal (seaweed).
Anchovy + ketchuptop 2% of all pairs

Smell alikestrong

Cooked together479 recipes

Shared aroma: ethanol (alcoholic, ethereal).
Cucumber + shallottop 3% of all pairs

Smell alikestrong

Cooked together264 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).
Cucumber + parsleytop 7% of all pairs

Smell alikestrong

Cooked together1,564 recipes

Shared aroma: trans-2-hexenal (green, leafy).
Egg + anchovytop 12% of all pairs

Smell alikemoderate

Cooked together2,330 recipes

Shared aroma: decanal (soap, orange peel).

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

What each ingredient does

Anchovy: Adds a salty, savoury depth that rounds out the sweet ketchup.
Hard-boiled egg yolk: Thickens the sauce slightly and adds a rich, creamy body.
Ketchup: Forms the sauce base, supplying sweetness and acidity.
Pickled cucumber: Contributes sharp acidity and crunch to balance the richness.

Swap the cucumber

How well each one fits the dish's main ingredients (ham, egg, anchovy, parsley, shallot, ketchup):

Chivefits better
Mustardfits better
Horseradishfits better
Cucumberthe original

Fit is the average pairing score against ham, egg, anchovy, parsley, shallot, ketchup. 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.