Name: Japanese Sandwiches
Ingredients: 12 sardines; 1 cup minced pickles; 1 cup minced celery; 1 cup mashed hard boiled egg; ½ teaspoon dry mustard; lemon juice to taste; bread

Why it works: Celery and mustard are a kitchen classic. They rank in the top 2% of all ingredient pairs, and cooks put them together in 4,169 recipes. Both carry guaiacol, which smells smoky, sweet. The science ↓

Japanese Sandwiches

Ingredients

Directions

Prepare the filling

Skin and bone the sardines, then mash them.
In a bowl, mix the mashed sardines with pickles, celery, hard boiled egg, dry mustard, and enough lemon juice to moisten.

Roll and fasten

Cut the bread into long thin strips.
Spread the sardine mixture on the bread and roll it up.
Fasten the rolls with toothpicks or tie with ribbon.

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.

Celery + mustardtop 2% of all pairs

Smell alikemoderate

Cooked together4,169 recipes

Shared aroma: guaiacol (smoky, sweet).
Celery + lemontop 3% of all pairs

Smell alikestrong

Cooked together3,467 recipes

Shared aroma: beta-phellandrene (minty, terpene).
Mustard + lemontop 11% of all pairs

Smell alikestrong

Cooked together3,816 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).
Egg + breadtop 13% of all pairs

Smell alikemoderate

Cooked together22,662 recipes

Shared aroma: (e)-2-octenal (fatty, green).
Mustard + breadtop 16% of all pairs

Smell alikemoderate

Cooked together1,484 recipes

Shared aroma: 2-acetyl-1-pyrroline (popcorn, roasted).

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

What each ingredient does

Sardines: Provide the main savory filling and body of the mixture.
Hard boiled egg: Adds softness and body to the filling, helping it hold together.
Pickles: Add acidity and a sharp, tangy bite that cuts the richness of the fish.
Celery: Adds crisp texture and a mild fresh crunch to the filling.