Name: John Dories, Boulogne Fashion
Ingredients: 1 ounce butter; 1 tablespoon flour; ¼ teaspoon salt; ¼ teaspoon pepper; a pinch of cayenne; ½ pint boiling milk; 1 teaspoon French mustard (or dissolved English mustard); juice of 1 lemon; 1 teaspoon cream

Why it works: Pepper and lemon match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 27,047 recipes. Both carry trans-2-nonenal, which smells cardboard, fatty. The science ↓

John Dories, Boulogne Fashion

Ingredients

Directions

In a saucepan, melt the butter over medium heat.
Stir in the flour, salt, pepper, and cayenne.
Add the boiling milk and stir well.
Mix in the mustard, lemon juice, and cream.
Heat until very hot, then serve over the fish or in a sauceboat with baked potatoes.

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 + lemontop 3% of all pairs

Smell alikestrong

Cooked together27,047 recipes

Shared aroma: trans-2-nonenal (cardboard, fatty).
Butter + milktop 7% of all pairs

Smell alikemoderate

Cooked together81,283 recipes

Shared aroma: (z)-4-heptenal (biscuit, cream).
Butter + creamtop 8% of all pairs

Smell alikemoderate

Cooked together41,516 recipes

Shared aroma: delta-dodecalactone (sweet, creamy).
Pepper + mustardtop 9% of all pairs

Smell alikemoderate

Cooked together15,430 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Mustard + lemontop 11% of all pairs

Smell alikestrong

Cooked together3,816 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).

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

Swap the mustard

How well each one fits the dish's main ingredients (butter, flour, pepper, milk, lemon, cream):

Potatofits better
Spinachfits better
Arrowrootfits better
Mustardthe original

Fit is the average pairing score against butter, flour, pepper, milk, lemon, cream. Candidates are from the same food group and used in at least 100 recipes.