Name: A Man's Sandwich
Ingredients: 6 pieces of toast; 12 slices of tomato; 6 crisp lettuce leaves; 12 slices of Bermuda onion; 3 tablespoons chopped parsley; mayonnaise; salt to taste

Why it works: Lettuce and parsley match in chemistry and in kitchens. They rank in the top 5% of all ingredient pairs, and cooks put them together in 1,483 recipes. Both carry trans-2-hexenal, which smells green, leafy. The science ↓

A Man's Sandwich

Ingredients

Directions

Prepare

Toast the bread until golden brown.

Assemble

Layer one lettuce leaf on each piece of toast.
Add 2 slices of tomato and 2 slices of onion on top of the lettuce.
Sprinkle with ½ teaspoon of chopped parsley.
Spread mayonnaise over the top and season with salt if needed.

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.

Lettuce + parsleytop 5% of all pairs

Smell alikestrong

Cooked together1,483 recipes

Shared aroma: trans-2-hexenal (green, leafy).
Tomato + lettucetop 6% of all pairs

Smell alikemoderate

Cooked together1,655 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Lettuce + oniontop 8% of all pairs

Smell alikestrong

Cooked together3,562 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Tomato + oniontop 8% of all pairs

Smell alikemoderate

Cooked together20,633 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Tomato + parsleytop 8% of all pairs

Smell alikemoderate

Cooked together5,398 recipes

Shared aroma: 4'-methylacetophenone (bitter almond).

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

What each ingredient does

Bread (in the method): Toasted slices form the sturdy base that holds the fillings together.
Tomato: Adds juiciness and a bright, acidic note that balances the mayonnaise.
Lettuce: Adds a crisp, cool texture that contrasts with the soft toast.
Bermuda onion: Contributes sharp, pungent flavor and a crunchy bite.
Mayonnaise: Adds fat and moisture, carrying flavor and softening the toast slightly.