Name: Egg Sandwich
Ingredients: 4 hard boiled eggs; 1 cucumber pickle; ¼ teaspoon pepper; ¼ teaspoon coarse sea salt; 1 tablespoon prepared mustard; 8 slices of bread; butter

Why it works: Cucumber and mustard match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 2,281 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Egg Sandwich

Ingredients

Directions

Prepare the filling

Chop the hard boiled eggs and cucumber pickle finely.
Add pepper, salt, and mustard; mix until smooth.

Assemble and serve

Spread the mixture between thin slices of buttered bread, with the crusts removed.
Arrange on a plate lined with a folded napkin.

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.

Cucumber + mustardtop 3% of all pairs

Smell alikestrong

Cooked together2,281 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Bread + buttertop 7% of all pairs

Smell alikemoderate

Cooked together27,232 recipes

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

Smell alikemoderate

Cooked together15,430 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Cucumber + peppertop 12% of all pairs

Smell alikemoderate

Cooked together5,991 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Egg + breadtop 13% of all pairs

Smell alikemoderate

Cooked together22,662 recipes

Shared aroma: (e)-2-octenal (fatty, green).

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

What each ingredient does

Hard boiled eggs: Provide the main body and richness of the filling.
Cucumber pickle: Adds tangy, acidic crunch that contrasts with the rich egg.
Prepared mustard: Adds sharp, pungent flavour that cuts through the richness of the egg.
Bread: Provides the structure that holds the filling and the butter's moisture barrier.

Swap the cucumber

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

Shallotfits better
Chivefits better
Asparagusfits better
Cucumberthe original

Fit is the average pairing score against egg, pepper, mustard, bread, butter. 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.