Lentil Soup
Red lentils, no soaking, and enough acid at the end to wake it up. A lentil soup without lemon in it tastes flat and nobody can say why.
- Prep
- 10 min
- Cook
- 35 min
- Total
- 45 min
- Serves
- 4
- Revisions
- 1
Allergens
- Celery
- Sulphites
Named from the ingredients as written, including those carried in from sub-recipes. This is not a guarantee — check the labels on what you actually buy, and note that a product’s recipe can change.
Ingredients
Serves
Soup
To finish
Method
Soup
Heat the oil and cook the onion, carrot and celery over medium heat for 10 minutes until soft.
Add the garlic, cumin, coriander and turmeric and stir for 90 seconds.
Stir in the tomato purée and cook for another minute until it darkens.
Add the rinsed lentils, the stock and the salt.
Red split lentils need no soaking and cook in about 25 minutes. They have had their skins removed, which is why they collapse into the soup rather than staying whole — brown or green lentils will not do that and make a different, brothier soup.
Simmer for 25 minutes, stirring occasionally and scraping the base, until the lentils have completely broken down.
Stir often towards the end. Lentils sink and catch, and a caught lentil soup tastes burnt all the way through.
Blend about half of it, or all of it, depending on whether you want texture. Left unblended it is also good.
To finish
Take it off the heat and add the lemon juice.
The lemon at the end is not a garnish. Lentils are earthy and starchy and a soup made without acid tastes flat in a way most people cannot identify — it is the single most common thing missing from a homemade lentil soup.
Taste for salt, and serve with parsley, a drizzle of good olive oil and a lemon wedge on the side.
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What to expect
- Taste
Earthy and savoury with cumin warmth over it, and then a sharp lemon lift that changes the whole thing. Taste it before and after the lemon goes in — it is the clearest demonstration in this collection of what acid does to a dish.
- Aroma
Cumin and fried onion.
- Texture
Thick and slightly velvety, with a faint graininess that is characteristic of red lentils and correct.
- Sound
The occasional slow bloop of a thick soup, which is also the warning to stir it.
- How the flavour moves
Earth and cumin first, then a long savoury middle, then lemon clearing the palate at the end.
- Serve it
Hot, and it holds heat well.
- Goes with
Flatbread, a sharp pickle, and more lemon. It is a complete meal with bread.
Cook's notes
- Difficulty
Beginner.
- Cost
The cheapest main course in this collection.
- Equipment
A heavy pan, and a blender if you want it smooth.
- When to make it
Any time. It is thirty-five minutes and costs almost nothing.
- Best season
None.
- You know it is done when
The lentils should have lost their shape entirely and the soup should be thick and slightly grainy-looking before blending.
- And it feels like
Thick enough to coat a spoon. It thickens considerably as it cools and will need loosening on reheating.
- Food safety
Red lentils need no soaking and no special treatment — unlike kidney beans, which contain a toxin requiring hard boiling, lentils have no such issue. Nothing unusual here.
- Where it goes wrong
- No acid at the end, which is why most homemade lentil soup is dull.
- Brown or green lentils, which do not break down.
- Not stirring near the end — lentils sink and catch, and a caught soup tastes burnt throughout.
- Adding the spices to liquid instead of frying them in oil.
- Under-salting a thick soup, which needs more than a thin one.
- Soaking the lentils, which is unnecessary and makes them mushy.
- If it does go wrong
Flat: lemon, then salt, then more lemon. Burnt: it caught on the base, and it cannot be saved — pour off the top without scraping and taste it. Too thick: water or stock. Grainy in a bad way: it needed a few more minutes.
- Making it ahead
Better the next day, and it freezes.
- Keeping it
Four days in the fridge, and it thickens each day.
- Reheating
With a splash of water, stirring, and add a fresh squeeze of lemon — the acid fades on standing.
- Freezing
Freezes very well for three months.
- Leftovers
Thicker the next day and good as a dal with rice.
- Scaling it
Doubles cleanly in a big enough pan.
- Substitutions
Yellow split lentils behave the same way. Tinned tomatoes, 200g, instead of the purée. Chicken stock makes it richer and not vegetarian.
- Dietary swaps
Vegan and dairy free as written, and one of the few genuinely filling main courses here that is. Celery and sulphites come from shop-bought stock only. Gluten free, egg free and nut free.
- Shopping for it
Lentils are far cheaper in a large bag from an international grocer than in a supermarket box.
- Keeping the cost down
300g of red lentils costs very little and feeds four generously. This is the cheapest way to feed people well in the entire collection.
- Sustainability
Lentils are one of the lowest-footprint protein sources there is and they fix nitrogen in the soil, so they improve the ground they grow in rather than depleting it. They are dried, so they store for years without refrigeration and travel efficiently, and nothing about this dish requires anything out of season. If any single recipe in this collection is the answer to eating well with a small footprint and a small budget at the same time, this is it.
- Nutrition
High in protein and fibre, low in fat, and genuinely one of the most nutritious things in this collection.
- Worth it?
One lemon, added off the heat. It is the difference between a soup people finish and one they do not.
Where it comes from
- Origin
The Near East, and very old.
- Also called
Shorbat adas in Arabic; mercimek çorbası in Turkish.
- Said out loud
SHOR-bat AH-das; mer-jee-MEK chor-bah-suh.
- What the name means
Literally lentil soup in both languages.
- History
Lentils are among the earliest domesticated crops, cultivated in the Fertile Crescent for something like ten thousand years, and they appear in some of the oldest written records of food there are. Lentil soup is therefore about as old as cooked food gets. The red split lentil, cumin and lemon combination is Levantine and Turkish and is everyday food across the region — in Turkey mercimek çorbası is served in almost every restaurant as a matter of course.
- Why it matters
Enormous, and mostly through sheer ubiquity. It is cheap, filling, meatless and eaten daily across a wide region, and it is a standard Ramadan iftar dish.
- When it is eaten
Everyday food, and specifically the everyday food of people who need to eat well cheaply.
- The traditional way
Softening aromatics, blooming spices in fat, and finishing with acid.
- How it changed
Very little. The blender is the only modern intervention.
- Regional variations
Turkish versions are often finished with a spoonful of chilli butter poured over. Egyptian ones use more cumin. Greek fakes uses whole brown lentils, vinegar and no blending, and is a different soup.
- How this version differs
Nothing unorthodox. The lemon is stated as a step with a reason rather than as an optional garnish, because it is the difference between a good version and a dull one.
- Sources and credit
None. This is a dish older than attribution.
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