Name: Calf's Head Hash
Ingredients: 1 tablespoon butter; 1 tablespoon flour; ½ cup cold milk; pepper to taste; coarse sea salt to taste; chopped meat from mock turtle soup; squares of toasted bread; celery tips for garnish; poached eggs (optional)

Why it works: Pepper and celery match in chemistry and in kitchens. They rank in the top 5% of all ingredient pairs, and cooks put them together in 16,012 recipes. Both carry 4'-methylacetophenone, which smells bitter almond. The science ↓

Calf's Head Hash

Ingredients

Directions

In a saucepan, melt the butter and stir in the flour.
Gradually add the cold milk while stirring, and bring to a boil.
Season with pepper and coarse sea salt, then add the chopped meat.
Place a spoonful of the mixture on each square of toasted bread.
Garnish with celery tips and serve. Optionally, top each square with a poached egg.

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 + celerytop 5% of all pairs

Smell alikestrong

Cooked together16,012 recipes

Shared aroma: 4'-methylacetophenone (bitter almond).
Butter + breadtop 7% of all pairs

Smell alikemoderate

Cooked together27,232 recipes

Shared aroma: delta-decalactone (sweet, creamy).
Butter + milktop 7% of all pairs

Smell alikemoderate

Cooked together81,283 recipes

Shared aroma: (z)-4-heptenal (biscuit, cream).
Milk + breadtop 11% of all pairs

Smell alikemoderate

Cooked together11,466 recipes

Shared aroma: 2-undecenal (sweet).
Butter + flourtop 12% of all pairs

Smell alikelow

Cooked together124,287 recipes

Shared aroma: isobutyraldehyde (malty, green).

Butter and flour barely smell alike, yet cooks put them together in 124,287 recipes: they work on texture and structure more than aroma.

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

Swap the celery

How well each one fits the dish's main ingredients (butter, flour, milk, pepper, meat, bread, egg):

Nutmegfits better
Parsleyfits better
Cinnamonfits better
Celerythe original

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