Name: Duck Sandwiches
Ingredients: smoked duck breasts, thinly sliced; hard-boiled eggs, thinly sliced; lemon juice; coarse sea salt; black pepper; butter; slices of bread

Why it works: Lemon and pepper 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 ↓

Duck Sandwiches

Ingredients

Directions

Layer thin slices of smoked duck on a slice of bread.
Add thin rings of hard-boiled eggs on top of the duck.
Squeeze a little lemon juice over the eggs.
Sprinkle with coarse sea salt and black pepper.
Cover with another slice of well-buttered bread.

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.

Lemon + peppertop 3% of all pairs

Smell alikestrong

Cooked together27,047 recipes

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

Smell alikemoderate

Cooked together27,232 recipes

Shared aroma: delta-decalactone (sweet, creamy).
Egg + breadtop 13% of all pairs

Smell alikemoderate

Cooked together22,662 recipes

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

Smell alikemoderate

Cooked together41,227 recipes

Shared aroma: 3-hexenal (apple, fruity).
Pepper + breadtop 16% of all pairs

Smell alikemoderate

Cooked together20,964 recipes

Shared aroma: 2-nonenal (fatty, green).

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

What each ingredient does

Smoked duck breasts: Provides the rich, savoury meat that forms the main filling.
Hard-boiled eggs: Add a soft, creamy texture that contrasts with the firm duck slices.
Butter: Adds richness and fat to the bread, softening the bite and helping it brown.
Lemon juice: Adds acidity that brightens the rich duck and egg.

“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.