Name: Hash Green Sandwiches
Ingredients: 3 hard cooked eggs; 1 onion, size of walnut; 1 green sweet pepper; 6 large lettuce leaves; ½ teaspoon dry ground mustard; ½ teaspoon paprika; 1 teaspoon salt; 1 tablespoon oil or melted butter; dash of cayenne pepper

Why it works: Lettuce and mustard match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 1,356 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Hash Green Sandwiches

Ingredients

Directions

Chop the eggs, onion, lettuce, and sweet pepper until minced.
In a bowl, combine the minced mixture with mustard, paprika, salt, and oil or butter. Mix well and spread between thin buttered slices of 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.

Lettuce + mustardtop 1% of all pairs

Smell alikestrong

Cooked together1,356 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Walnut + lettucetop 1% of all pairs

Smell alikestrong

Cooked together491 recipes

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

Smell alikestrong

Cooked together9,259 recipes

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

Smell alikestrong

Cooked together3,562 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Walnut + mustardtop 9% of all pairs

Smell alikestrong

Cooked together849 recipes

Shared aroma: eucalyptol (eucalyptus, herbal).

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

What each ingredient does

Hard cooked eggs: Provide the main body and creamy texture of the filling.
Onion: Adds sharp aromatic flavor that cuts through the richness of the eggs.
Oil or melted butter: Adds fat that coats the chopped filling and carries flavor, keeping it moist.
Dry ground mustard: Adds pungent, sharp flavor that balances the richness of the eggs.

Swap the onion

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

Chivefits better
Spinachfits better
Shallotfits better
Onionthe original

Fit is the average pairing score against egg, walnut, pepper, lettuce, mustard, 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.