Name: Leek Soup
Ingredients: 1 bunch of leeks; 3 quarts of good stock; 2 tablespoons of butter; pepper to taste; coarse sea salt to taste; fried bread, cut into dice

Why it works: Butter and bread are a kitchen classic. They rank in the top 7% of all ingredient pairs, and cooks put them together in 27,232 recipes. Both carry delta-decalactone, which smells sweet, creamy. The science ↓

Leek Soup

Ingredients

Directions

Prepare

Cut and wash the leeks.
Put the leeks into a pot with the stock.

Cook and finish

Boil until the leeks are tender enough to pulp through a sieve.
Add butter, pepper, and salt to taste.
Serve with fried bread cut into dice.

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.

Photo for illustrative purposes only · Contact us to use it

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.

Butter + breadtop 7% of all pairs

Smell alikemoderate

Cooked together27,232 recipes

Shared aroma: delta-decalactone (sweet, creamy).
Leek + peppertop 12% of all pairs

Smell alikemoderate

Cooked together965 recipes

Shared aroma: coumarin (sweet, hay).
Leek + breadtop 13% of all pairs

Smell alikemoderate

Cooked together279 recipes

Shared aroma: 1-octen-3-ol (mushroom, earthy).
Leek + buttertop 15% of all pairs

Smell alikemoderate

Cooked together848 recipes

Shared aroma: trans-2-hexenal (green, leafy).
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

Leeks: Provide the main flavor and body, softening into a pulpable base for the soup.
Stock: Supplies the liquid that cooks the leeks and forms the body of the soup.
Butter: Adds fat and richness, giving the soup a smoother, rounder mouthfeel.

The step that matters

Boil until the leeks are tender enough to pulp through a sieve. If the leeks are underdone they will not break down into a smooth purée, leaving a gritty, fibrous texture. Cooking until fully soft lets the cell walls break so the vegetable passes through the sieve.