Name: Thick Vegetable Soup
Ingredients: 1 lb French beans, sliced; ½ lb lentils; ½ lb peas; 2 quarts stock; 1 carrot, chopped; 2 onions, chopped; 1 oz butter; stale bread, cut into different patterns

Why it works: Beans and lentils match in chemistry and in kitchens. They rank in the top 1% of all ingredient pairs, and cooks put them together in 135 recipes. Both carry coumarin, which smells sweet, hay. The science ↓

Thick Vegetable Soup

Ingredients

Directions

Make the soup

Put the French beans, lentils, peas, stock, carrot, and onions in a large saucepan and bring to a boil.
Once cooked, crush the vegetables and pass them through a colander into another saucepan.
Gradually add stock to thin the soup and bring it to a boil for 20 minutes.

Prepare the bread and serve

Melt the butter in a frying pan.
Fry the stale bread on low heat until golden.
Place the fried bread in a tureen.
Strain the soup over the fried bread.
Serve hot.

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.

Beans + lentilstop 1% of all pairs

Smell alikestrong

Cooked together135 recipes

Shared aroma: coumarin (sweet, hay).
Beans + carrottop 4% of all pairs

Smell alikestrong

Cooked together1,443 recipes

Shared aroma: 2-isobutyl-3-methoxypyrazine (green bell pepper, earthy).
Lentils + carrottop 5% of all pairs

Smell alikestrong

Cooked together505 recipes

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

Smell alikestrong

Cooked together949 recipes

Shared aroma: 2-isobutyl-3-methoxypyrazine (green bell pepper, earthy).
Carrot + oniontop 6% of all pairs

Smell alikemoderate

Cooked together21,601 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

French beans: Provide bulk and body, thickening the soup as they break down.
Lentils: Thicken the soup and add substance through their starch as they cook.
Peas: Add body and a soft, smooth texture when crushed and strained.
Onions: Add savoury depth and sweetness as they soften during cooking.
Butter: Adds richness and flavour to the bread used for frying.

The step that matters

Gradually add stock to thin the soup. Adding the stock slowly lets you control the thickness, since the purée thickens quickly as starch and fibre from the vegetables and lentils absorb liquid. Adding it all at once can leave the soup too thin or lumpy, and boiling it for 20 minutes keeps the flavour concentrated.

Swap the onion

How well each one fits the dish's main ingredients (beans, lentils, peas, carrot, butter, bread):

Leekfits better
Lettucefits better
Turnipfits better
Onionthe original

Fit is the average pairing score against beans, lentils, peas, carrot, butter, 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.