This is a fifty-minute recipe on the hob, not a slow cooker one. Red lentils go from dry to completely broken down in under half an hour, and nothing about that benefits from being stretched over hours.
The first minute after the aromatics is where the colour comes from. Curry paste and turmeric cooked in oil for sixty seconds bloom into the deep orange the finished soup carries.
Why This Recipe Works
- Cooking the curry paste and turmeric briefly in oil releases their fat-soluble colour and aroma before any liquid arrives.
- Red lentils collapse completely, which thickens the soup without a blender or any starch.
- Full-fat coconut milk gives the richness that keeps a lentil soup from tasting austere.
- Lime juice goes in off the heat, where its brightness survives.
Ingredient Notes
- Red lentils
- A cup and a half, rinsed. Red specifically — they are meant to break down completely.
- Thai red curry paste
- Two tablespoons, cooked in the oil for a minute before the liquid goes in.
- Full-fat coconut milk
- One 13.5-ounce can. Full-fat, for the richness and the colour.
How to Make It
Aromatics and paste
Heat the oil in a soup pot over medium heat. Cook the onion for 5 minutes, then add the garlic, ginger, curry paste and turmeric and cook 1 minute.
Lentils and liquid
Add the red lentils, broth, coconut milk and salt. Bring to a gentle boil, then reduce to a simmer.
Simmer until thick
Cook 22 to 28 minutes, stirring occasionally, until the lentils collapse and the soup becomes thick and orange.
Finish
Stir in the lime juice. Serve with cilantro, chilli oil streaks and lime wedges.
Four Steps to a Thick Orange Soup
Fifty minutes end to end, and each rung changes the pot in a way the next one depends on.
Soften5 minutes, until translucent.
A diced yellow onion in a tablespoon of neutral oil over medium heat. Nothing else is in the pot yet.
Bloom1 minute only - any longer and the paste catches.
Garlic, grated ginger, 2 tbsp of Thai red curry paste and 1 tsp of turmeric stirred into the hot oil. This is where the soup gets its colour and most of its aroma.
Simmer22 to 28 minutes, stirring occasionally.
1 1/2 cups of rinsed red lentils, 4 cups of vegetable broth, a 13.5 oz can of full-fat coconut milk and a teaspoon of salt. Brought to a gentle boil, then dropped to a simmer.
CollapseThick and orange, holding a spoon's trail.
The lentils lose their shape entirely and thicken the soup as they go. No blending and no slurry - this is the whole thickening mechanism.
Success Tips
- Rinse the lentils until the water runs clear — the starch they shed otherwise makes the soup gummy rather than thick.
- Give the curry paste its full minute in the oil. Adding it with the broth wastes most of its aroma.
- Stir occasionally as it simmers; lentils that have collapsed will catch on the base if left alone.
Serving Ideas
Six servings, thick and orange, with chopped cilantro, streaks of chilli oil and lime wedges alongside.
Frequently Asked Questions
Can I make this in a slow cooker?
This is a stovetop recipe. It takes under an hour, and the red lentils do not need a long cook.
My soup is thin. What went wrong?
It probably needs longer. The lentils have to collapse completely, which takes 22 to 28 minutes at a simmer.
Can I use green or brown lentils?
No. They hold their shape, and this soup depends on the lentils breaking down.
