AI-generated illustration of four bowls of smooth orange carrot and red lentil soup without garnish

Soup

Spiced Carrot and Red Lentil Soup

Published 29 October 2026 · Updated 29 October 2026

Sweet carrots and red lentils make a thick orange soup with earthy cumin, warm ginger and a little chilli. Gently softening the onion before simmering builds the savoury base, while lemon sharpens the blended soup at the finish.

Not kitchen tested by The Black Farmer.

Research: three complete external recipes compared. Editorial review: separate whole-recipe review completed. Kitchen testing: not performed.
Serves 4
Prep 20 min
Cook 56 min
Total 76 min

Timing: Untested sequential baseline: 18 minutes preparation, 56 cooking/processing/finishing and 2 off-heat settling = 76 minutes. Display prep 20 is active prep18 plus cooling2; the cooling still occurs after simmering, not before cooking. All parallel_group values are null: no overlapping tasks, soaking, planned rest or stock-making stage. Ready-to-use stock avoids an uncounted kettle stage. Conditional segments start at zero only in the baseline and add actual time: slower prep, onion softening, boil-up, repeated five-minute tenderness cycles, appliance cooling, motor pauses, transfers, blending and reheating. Extra time has no fixed upper bound. Bread/rarebit timing is separate.

Ingredients

  • Carrots - 500g

    Carrots

    650g prepared weight

    Wash, peel and trim, then weigh 650g; slice into 4mm half-moons, quartering thick carrots lengthways first so pieces are no more than about 20mm across. Buy two 500g whole-carrot packs (1kg gross); use only the weighed prepared amount. Keep any surplus for another meal.

    £1.00

Adds 2 items across 1 products — £2.00 total.

Pantry ingredients such as oil, salt and herbs are not included.

Other Ingredients You'll Need

  • Dried split red lentils — 180g (Pick over, rinse thoroughly in a fine sieve and drain; do not substitute canned or whole lentils.)
  • Onion — 150g peeled weight (Weigh 150g after peeling, then cut into 5mm dice. Onion sizes vary; buy enough to supply the prepared weight.)
  • Rapeseed oil — 20ml (All for warming the pan and softening the onion; none reserved for a drizzle.)
  • Garlic — 8g (Peeled weight; finely chop. All added with ginger.)
  • Fresh ginger — 12g (Peeled weight; finely grate. All added with garlic.)
  • Ground cumin — 4g (Ground spice, not whole seeds; all bloomed in the onion oil.)
  • Dried chilli flakes — 0.3g (All added with cumin. Strength varies; restrained quantity is not a guaranteed mild result.)
  • Vegetable stock — 1.3 litres ready-to-use liquid (Mild reduced-salt ready-to-use liquid, not concentrate. Baseline uses a newly opened shelf-stable carton at room temperature, according to label storage. Chilled stock goes straight from fridge to pan and may take longer to heat; do not leave chilled stock out to warm. Check stock allergens.)
  • Water — Up to 200ml total, only if needed (One measured reserve for the whole recipe. Add only if needed during simmering or after blending in 50ml portions; do not start a fresh reserve at either stage.)
  • Lemon juice — 25ml (Freshly squeeze and measure during preparation; all stirred in after reheating.)
  • Ground black pepper — 0.5g (All stirred in with lemon at the finish.)
  • Fine salt — Up to 2g, only if needed (Conditional finishing allowance, not a compulsory addition. Taste first because stock salinity varies.)

Method

Prepare the vegetables and lentils

Allow about 18 minutes for preparation and equipment checks. Wash, peel, trim and weigh 650g carrots. Slice into 4mm half-moons, quartering thick carrots lengthways first so pieces are no more than about 20mm across. Dice the weighed peeled onion into 5mm pieces, chop the garlic and grate the ginger. Pick over the dried split red lentils, rinse thoroughly in a fine sieve and drain; no soaking. Measure the oil, cumin, chilli flakes, ready-to-use stock, lemon juice, pepper and conditional salt, using 0.1g-reading scales for the small spice quantities. Measure a single 200ml water reserve for the whole recipe. Use a deep heavy lidded saucepan of at least 5 litres, roughly 22–24cm wide; keep contents below two-thirds full or any lower maker limit. Check the immersion blender’s hot-liquid temperature, minimum immersion and duty-cycle instructions before starting; choose a compatible deeper vessel if needed.

Sweat the onion

Warm all 20ml rapeseed oil in the pan over medium-low heat for about 1 minute, without smoking. Add all the onion and cook for about 9 minutes, stirring, until soft and translucent rather than crisp or deeply browned. Lower the heat if the edges darken; continue gently if still firm, counting any extra softening time.

Cook the aromatics and spices

Stir in all the garlic and ginger and cook on low to medium-low for about 2 minutes, until fragrant without darkening. Add all the ground cumin and dried chilli flakes; stir over low heat for about 1 minute so the spices smell aromatic rather than scorched. Move directly to the liquid stage.

Load the pan and bring to the boil

Add all the prepared carrots, drained lentils and 1.3 litres vegetable stock. Stir across the base to release the spice mixture. Bring to the boil over medium-high heat with the lid slightly ajar, watching for foam and stirring so nothing sticks. Allow about 8 minutes for loading, stirring, skimming any thick foam and heating; colder stock or a slower hob may need longer. Do not start the simmer allowance until the liquid is visibly bubbling.

Simmer until both carrots and lentils are soft

Reduce to low and keep the lid slightly ajar. Simmer gently for about 25 minutes, stirring regularly across the bottom and turning exposed carrot pieces into the liquid. Lower the heat if it catches or boils hard. If it thickens before the lentils soften, add 50ml at a time from the single measured water reserve. A thick carrot slice must crush easily against the pan and the lentils must have broken down with no firm or gritty centre. If either is still firm, continue in further 5-minute simmer-and-check cycles until tender; every cycle adds time. Do not blend hard vegetables to meet a deadline.

Settle off the hob, then blend

Take the pan off the hob onto a stable heatproof surface, protecting your hands from hot handles and keeping clear of steam. Allow about 2 minutes for vigorous bubbling to subside. This is not a safe-temperature guarantee: follow the hot-liquid-rated immersion blender’s temperature limit, measuring if specified, and wait longer if required. Check that the guard can stay fully submerged at the maker’s required depth, below the safe fill line. If not, stop and use a suitable deeper vessel only when safe to handle; never tilt the pan or run exposed blades. Allow about 4 minutes to blend off the hob until evenly orange and freely pourable, accepting fine flecks. Start low with the guard submerged and stop the motor before lifting it out. Disconnect before clearing or touching blades. Follow required motor pauses and count extra time. If too thick, stop and stir in 50ml portions from the remaining measured water reserve: no more than 200ml across simmering and blending combined. Do not use a sealed jug or smoothie cup.

Reheat gently

Remove and disconnect the blender. Return the soup to the saucepan if transferred and warm over low to medium-low heat for about 4 minutes, stirring across the base, until steaming hot throughout. Avoid a hard spluttering boil. Any longer appliance cooling, extra transfer or added water can require more reheating; count the actual additional time. The intended texture is thick but freely pourable, not a mound that holds its shape.

Sharpen, season and serve

Switch off the heat. Allow about 2 minutes to stir in all 25ml lemon juice and 0.5g ground black pepper, taste a small cooled spoonful, add fine salt only if needed within the 2g allowance, and ladle equally into four bowls. Serve straight away.

Serving Suggestion

Serve with toasted wholemeal bread or plain oatcakes, prepared separately. For a more substantial lunch, add Welsh Rarebit on toast alongside, noting its separate ingredients, allergens and preparation time. Neither accompaniment is included in the four soup portions or timetable.

Frequently Asked Questions

Can I use tinned lentils instead?

Not directly. This method needs dried split red lentils to absorb liquid and break down into the carrot base. Tinned or whole lentils have different hydration and texture, so they are not a like-for-like substitution.

Why is the soup sticking before the lentils are soft?

Lentils thicken the liquid as they soften. Keep the simmer gentle, stir across the bottom and use the measured water reserve as directed rather than raising the heat. Complete tenderness, not thickness alone, determines when to blend.

How is this different from carrot and coriander soup?

The dried split lentils are essential to the body of this soup, and the flavour comes from cumin, ginger, a little chilli and late lemon. It does not use ground or fresh coriander, milk or cream.

Does it need to be completely smooth?

Blend until the carrots are no longer in distinct pieces and the soup pours evenly. Fine flecks are acceptable; do not run the blender beyond its permitted duty cycle to chase a perfectly silky texture.

Why buy two packs but use 650g carrots?

Each pack contains 500g whole carrots before peeling and trimming. Buy two packs, weigh the prepared quantity and keep any surplus for another meal; the purchased kilogram is not the amount added to the soup.