Sweet Potato, Lentil and Chilli Soup

This sweet potato and lentil soup is warming, filling and exactly the sort of thing I make when I want something homemade without too much effort. It is smooth, comforting and gently spicy with sweet potatoes for natural creaminess and lentils to make it more satisfying.

I usually make this in my soup maker for ease and speed – everything goes in, the button goes on, and I can get on with something else while it cooks. I’ve also included the traditional hob method below, plus tips for using a stick blender or jug blender.

It is brilliant for chilly days, busy lunchtimes, batch cooking, or those evenings when you want something warm and useful rather than complicated.

Why I keep coming back to this soup

This is one of those recipes that uses ingredients I often already have in: sweet potatoes, lentils, onion, chilli and stock.

The sweet potato makes the soup naturally creamy, the lentils make it wonderfully creamy, and the chilli gives it a bit of warmth. We like to make it quite spicy so use a combination of chilli powder and chilli flakes. We also like the extra riches of about 3 tablespoons of double cream but this is completely optional.

It is also really budget-friendly and freezes well, which makes it a handy one to have ready for quick lunches.

Ingredients for sweet potato and lentil soup

Exact amounts are listed in the recipe card below.

Sweet potatoes – These give the soup its lovely colour, sweetness and creamy texture. Peel and chop them into small chunks so they cook evenly if cooking on the hob. Your pieces can be chunky and rustic if you are using a soup maker.

Red or yellow split lentils – I usually use Red lentils because they cook quickly and blend smoothly, but yellow split lentils work well too. The version photographed here used yellow lentils because that is what we had in. I soaked the yellow lentils for a couple of hours first in cold water to help them cook more quickly.

Onion – Either red or yellow onion to add flavour. I start most of my soup recipes with a chopped onion.

Red chilli or chilli powder – I tend to use hot chilli powder as this recipe is definitely about what is in the cupboard. A fresh red chilli also works well. Remove the seeds for a milder soup. We also add some red chilli flakes so extra heat.

Vegetable stock – A stock cube, stock pot or stock powder is fine. Use low-salt stock if cooking for children.

Water – If using a soup maker, add water to the max fill line. If cooking on the hob, you can add a little more or less depending on how thick you like your soup.

Cream, yoghurt or coconut milk – Optional for serving or thickness. I usually keep this soup simple, but a small swirl looks lovely and softens the chilli heat.

Red lentils or yellow lentils?

I usually make this soup with red split lentils because they cook quickly and break down well, which makes the soup smooth and thick.

Yellow split lentils can also be used. They may take a little longer to soften, so I like to soak them in cold water for a few hours first, then drain and rinse before adding them to the soup maker or pan.

If you are using a soup maker, make sure the lentils are split lentils rather than whole lentils, and do not fill the soup maker above the maximum line.

How spicy is this soup?

As spicy as you like it! This is a warming soup rather than a blow-your-head-off soup but I do think it benefits from a generous heat.

One red chilli gives gentle heat, especially if you remove the seeds. For a milder soup, use half a chilli or a small pinch of chilli powder. For more heat, keep the seeds in, use extra chilli powder, or add chilli flakes to adult portions at the end.

How to make sweet potato and lentil soup in a soup maker

I usually make this soup in our Morphy Richards Soup Maker, which has been one of the most useful kitchen gadgets we’ve ever bought. I’ve written a full Morphy Richards Soup Maker review after more than ten years of using one if you’re wondering whether they’re worth buying.

This is the way I usually make it.

Peel and chop the sweet potatoes into chunks (About 2cm wide).

Drain and rinse the soaked yellow lentils, or rinse red split lentils under cold water until the water runs mostly clear.

Add the sweet potato, lentils, chopped onion, chilli and vegetable stock to the soup maker.

Add water up to the correct fill line for your soup maker.

Choose the smooth soup setting.

Once cooked, taste and adjust the seasoning if needed.

Serve hot, with cream, yoghurt, coconut milk or crusty bread/croutons if you like. I also went fancy and added some chopped chives straight from the garden (Chopped coriander also works well).

How to make it on the hob

You can also make this soup in a normal pan.

1. Peel and chop the sweet potatoes into small chunks.
2. Rinse the lentils well. If using yellow split lentils, soak them first if you have time.
3. Heat a little oil in a large pan and gently cook the onion for a few minutes until softened.
4. Add the sweet potatoes, lentils, chilli, vegetable stock and water.
5. Bring to the boil, then reduce the heat and simmer for around 20–25 minutes, or until the sweet potato and lentils are completely soft.
6. Blend until smooth using a stick blender, or allow to cool slightly and blend carefully in a jug blender.
7. Add a splash more water or stock if the soup is too thick.

Using a stick blender or jug blender

A stick blender is the easiest way to blend this soup if you are making it in a pan. You can blend it straight in the saucepan and stop when it is as smooth as you like.

A jug blender will give a very smooth finish, but be careful with hot soup. Let the soup cool slightly first, blend in batches, and never overfill the blender.

Tips for the best sweet potato and lentil soup

• Rinse the lentils before cooking to remove any excess starch.
• Chop the sweet potato fairly small so it cooks quickly and blends smoothly.
• Do not add too much chilli at the start if you are making this for children. You can always add chilli flakes, chilli oil or black pepper to individual bowls later.
• If the soup is too thick after blending, add a little hot water or stock until it is the consistency you like.
• If the soup tastes a bit flat, add a squeeze of lemon or lime juice before serving. It brightens everything up.
• If using a soup maker, always stay within the minimum and maximum fill lines.

What to serve with sweet potato and lentil soup

This soup is filling enough for lunch on its own, but it is lovely with something on the side.

Try it with:

• Homemade croutons
• crusty bread
• garlic bread
• cheese on toast
• naan bread
• toasted pitta
• a simple sandwich
• savoury muffins

We have served it with garlic bread before on a night when comfort food was very much needed, and it worked surprisingly well.

Can I make this soup ahead?

Yes, this soup is great for making ahead. Let it cool, then store it in an airtight container in the fridge.

It will keep for up to 3 days in the fridge. Reheat gently in a pan or microwave until piping hot, adding a splash of water or stock if it has thickened.

Can I freeze sweet potato and lentil soup?

Yes. Let the soup cool completely, then freeze in portions for up to 3 months.

Defrost overnight in the fridge, then reheat until piping hot. The soup may thicken slightly after freezing, so add a little water or stock when reheating if needed.

Useful equipment

You do not need anything fancy to make this soup, but these are useful if you make soup regularly.

Soup maker – Ideal if you want a hands-off soup with minimal washing up. We have had ours for years and love it.

Stick blender – Great for blending soup directly in the pan. Again, we’ve had ours for years since blending up the girls’ food when they were babies.

Jug blender – Useful if you like a very smooth soup, but take care when blending hot liquids.

Soup containers – Handy for fridge portions, freezer batches or work lunches.

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Frequently asked questions

Can I use yellow lentils instead of red lentils?

Yes. Red split lentils are my usual choice because they cook quickly and blend smoothly, but yellow split lentils work too. If using yellow lentils, soak them for a few hours first, then drain and rinse before cooking.

Do I need to cook the lentils before adding them to the soup maker?

No, not if you are using red split lentils or soaked yellow split lentils. Rinse them well first, then add them to the soup maker with the other ingredients.

Can I make this soup without a soup maker?

Yes. Cook everything in a pan until the sweet potato and lentils are soft, then blend with a stick blender or jug blender.

Can I make this soup milder?

Yes. Use half a chilli, remove the seeds, or swap the fresh chilli for a small pinch of chilli powder. You can always add extra heat to individual bowls later.

Can I add coconut milk?

Yes. Coconut milk works really well with sweet potato and chilli. Add a splash at the end, or replace some of the water with coconut milk if your soup maker allows it.

Why is my soup too thick?

Lentils continue to thicken as they cook and as the soup sits. Add a splash of hot water or stock and stir until it loosens.

Is sweet potato and lentil soup vegetarian?

Yes, as long as you use vegetable stock. To keep it vegan, serve without cream, or use coconut milk or dairy-free yoghurt instead.

Can I freeze this soup?

Yes. Freeze in portions for up to 3 months. Defrost overnight in the fridge and reheat until piping hot.

More easy comfort food recipes

If you like easy, filling recipes made with everyday ingredients, you might also like my Homemade Pot Noodle, Storecupboard BBQ Couscous or Chicken Casserole with Herby Dumplings.