Name: Neapolitan Vegetable Soup
Ingredients: 2 pounds ripe tomatoes; 5 large peeled potatoes; 1 handful washed and picked sorrel; 2.5 pints water; salt to taste; 1.5 to 2 ounces butter; 0.75 ounces loaf sugar; pepper to taste; small pieces of bread fried in butter

Why it works: Potato and sorrel work together. They rank in the top 5% of all ingredient pairs, and cooks put them together in 72 recipes. Both carry coumarin, which smells sweet, hay. The science ↓

Neapolitan Vegetable Soup

Ingredients

Directions

Make the soup

Boil tomatoes, potatoes, and sorrel in water with a little salt until thoroughly cooked.
Pass the mixture through a sieve.
Return the liquid to the fire and add butter and loaf sugar.
Season with pepper and salt, and simmer for a few minutes.

Serve

Fry small pieces of bread in butter and place them in a tureen.
Pour the soup over the fried 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.

Potato + sorreltop 5% of all pairs

Smell alikemoderate

Cooked together72 recipes

Shared aroma: coumarin (sweet, hay).
Tomato + potatotop 5% of all pairs

Smell alikestrong

Cooked together2,798 recipes

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

Smell alikemoderate

Cooked together27,232 recipes

Shared aroma: delta-decalactone (sweet, creamy).
Tomato + peppertop 7% of all pairs

Smell alikemoderate

Cooked together17,923 recipes

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

Smell alikemoderate

Cooked together8,305 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).

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

What each ingredient does

Tomatoes: Provide the main body, acidity and fresh flavour of the soup.
Potatoes: Break down during boiling to thicken the soup and give it body.
Sorrel: Adds a sharp, lemony acidity that brightens the soup.
Butter: Adds richness and a smooth, rounded mouthfeel to the finished soup.
Loaf sugar: Balances the acidity of the tomatoes and sorrel with gentle sweetness.

The step that matters

Passing the mixture through a sieve. Pushing the cooked vegetables through a sieve breaks down their fibres and starch, producing a smooth, even texture. Skipping or rushing this step leaves the soup grainy or uneven.

Swap the sorrel

How well each one fits the dish's main ingredients (tomato, potato, butter, sugar, pepper, bread):

Thymefits better
Parsleyfits better
Cinnamonfits better
Sorrelthe original

Fit is the average pairing score against tomato, potato, butter, sugar, pepper, bread. 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.

Tomato Soup526 recipes

Brown Bread461 recipes

Potato Croquettes255 recipes

Cream of Tomato Soup107 recipes

Like knowing why a recipe works?

The free Flavor Lab newsletter: one surprising pairing a week and the molecular reason it works, in 60 seconds. No spam, unsubscribe anytime.

Prefer an account? Create a free account to save pairings and unlock the full chemistry.

Neapolitan Vegetable Soup