Name: Instant Pot Red Lentil Soup
Prep time: 10 min
Cook time: 8 min
Total time: 28 min
Ingredients: 1 tablespoon olive oil ((omit to make oil-free and use some water to sauté instead)); 1 large onion (, diced); 3 ribs celery (, diced); 2 large carrots (, diced); 5 cloves garlic (, chopped finely); 3 - 4 large potatoes (, cubed); 300 grams / 1½ cups split red lentils; 1 tablespoon dried mixed herbs (, I like to use Italian mixed herbs, or Herbs De Provence); 2 teaspoons salt; ½ teaspoon freshly ground black pepper; 8 cups / 1920 mls vegetable stock; 1 tablespoon sugar (see notes); 2 to 3 fresh lemons; 4 - 5 big handfuls chopped greens (, (spinach, kale, chard or collard greens))

4.87 from 22 votes

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This easy recipe for Instant Pot Red Lentil Soup is the perfect way to get an easy and healthy meal on the table in under 30 minutes. This delicious vegan soup features simple, budget-friendly ingredients and is great for meal prep, weeknight dinners, or to freeze for later!

a bowl of red lentil soup with a pot of vegan butter and bread

Let's fill our bowls with this nutrient-dense, colourful, hearty and super delicious Instant Pot Red Lentil Soup. Loaded with fresh vegetables, potatoes, greens, soft red lentils, and plenty of lemon juice, every spoonful is vibrant and filling. Maybe a tumble of golden vegan croutons too?

The Instant Pot will work its magic and cut down the cooking process so your soup is ready quickly and with next to zero effort. If you don't have an Instant Pot though, don't worry because you can find my regular lemony red lentil soup here.

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Do red lentils need to be soaked?
Ingredients
How to make red lentil soup in your Instant Pot
Slow cooker red lentil soup
Success tips
Ways to adapt this recipe
What to serve with red lentil soup
Storing, freezing, & reheating
Hungry for more?
Recipe
Reviews & Questions

Serve alongside some bread and vegan butter, maybe a fresh and lemony Quinoa Cranberry Salad, and you'll have a wholesome lunch or dinner the whole family will love.

Do red lentils need to be soaked?

You’re in luck because uncooked split red lentils do not have a tough outer shell and break down very easily once cooked. This means there is no soaking involved.

Because they break down easily, red lentils are best used in soups, stews or Indian Dal dishes, and any soup-like meal where you want a thick and hearty base. Having said that I do use them in my vegan meatloaf, because they are so soft and help stick everything together. If you want to add lentils to a salad or cold dish, use a variety that holds its shape well, like green lentils.

Because of the way dry lentils are stored, they tend to retain some dust and dirt in their package. This is why it’s a great idea to rinse them under cold water using a colander or sieve before cooking. Make sure you check for small stones or dirt while rinsing as well.

Ingredients

(For detailed measurements and instructions, see the printable recipe card).

All of these ingredients should be easy to find in your local grocery store. Dried red lentils and soup vegetables are fairly inexpensive, so you’re able to stick to a small budget.

You’ll need an Instant Pot or electric pressure cooker to make this dish. If you don’t have one, follow the instructions over at my recipe for Red Lentil Soup with Lemon. It’s made on the stovetop and is pretty much the same.

Here are the ingredients you’ll need to make this light, fresh, and tangy lentil and lemon soup:

ingredients for Instant Pot Red Lentil Soup as per the listed ingredients in the recipe card

Split red lentils - Found in just about every grocery store. They are orange in colour and are thinner than regular lentils. They work well here because they have a delicate, earthy, slightly sweet flavour and they break down almost completely, giving the soup a really thick and hearty texture.
Soup vegetables - You’ll need the classic mirepoix, or mix, of aromatic vegetables in this soup such as carrots, celery, onion, and garlic.
Potatoes - Yellow potatoes add great texture and heartiness to soup recipes.
Dried herbs - Feel free to use a mix of dried rosemary, thyme, or basil. You could also keep it simple and use an herb blend like Italian or Herbs De Provence instead.
Vegetable stock - This is the base of the soup and helps add lots of flavour. You'll notice there is quite a lot of stock added. That's because lentils absorb lots of liquid and we don't want it getting too thick because the burn error could be triggered on the Instant Pot.
Sugar - This is important for balancing flavours, just like salt, especially in a very acidic recipe like this one (hellooo lemon!). You won’t need much but it will make a huge difference to the balance of flavour.
Lemons - Fresh lemon juice adds flavour and acidity that pairs well with the red lentils and the greens vegetables. It's what really makes this soup so good!
Greens - My go-to green for this soup is usually kale because it's robust and flavourful, keeps its shape and texture really well and has plenty of nutrients. Spinach (fresh or frozen), Swiss chard, collard greens, Savoy cabbage, or beet greens all work well too. Just use what you have or can get hold of easily. I actually used spinach when I made this recipe to photograph because it's what I had on hand.

How to make red lentil soup in your Instant Pot

This recipe is really simple to throw together and doesn’t require any fancy steps. Simply saute a few of the vegetables to begin, then let your Instant Pot take care of the rest! Here’s how it’s done:

Step 1 - Saute the onion, carrot and celery in the Instant Pot with oil (or some water if you want to keep the recipe oil-free).

sautéed onions, carrot and celery in an Instant Pot

Step 2 - Add in the garlic and let it cook in the residual heat, then add everything else (except the greens and lemon) and give it a stir. It doesn't look appealing at this stage!

Step 3 - Cook for 10 minutes then leave the pressure to naturally release for 10 minutes then open.

cooked red lentil soup in an Instant Pot

Step 4 - Stir in the greens then switch to saute to let them cook for a few minutes if necessary. You won't need to if you use spinach.

Step 5 - Turn off and stir in the lemon juice, check the seasonings and serve!

Slow cooker red lentil soup

Don’t have an Instant Pot? This recipe can be made in your crockpot or slow cooker instead:

Step 1: Begin by sauteing all of the vegetables in a skillet. This will help draw out lots of flavour.

Step 2: Transfer everything into the slow cooker (except the lemon and greens) and cook on high for 3 hours or low for 5 to 6 hours.

Step 3: Once everything is tender, add the greens and allow them to wilt down. Turn off the heat. Add the lemon juice and serve.

Success tips

This recipe has only been tested with red lentils. Using a different lentil will change the cooking time and texture of the soup.
Canned lentils are not recommended in this recipe as they will end up very overcooked.
It’s important that you add your greens AFTER the soup is cooked as they will not hold up well under the pressure. Allow them to wilt naturally in the heat of the finished soup for the best results and texture.
Don't reduce the amount of liquid or increase the amount of lentils. When cooking in an Instant Pot it is important for the soup not to get too thick or you could end up triggering the burn error. This recipe has been carefully tested to keep the ratio of lentils to water just right.

close up of a bowl of red lentil soup with lemon slice garnish

Ways to adapt this recipe

Use any greens that you have on hand. If you want to use spinach, just know that it will wilt as soon as it’s added into the hot soup so you can skip the simmering step at the end.
I like it left chunky, but you can use an immersion blender right in the Instant Pot to thicken and smooth the soup to your desired texture if you want to.
Although lemon gives the soup its optimal flavour, it can be omitted from the recipe if needed.
For a creamy red lentil soup, add a can of coconut milk after it’s cooked. Simply use the saute button to simmer it for a few minutes to warm through.
Instead of using herbs, use a couple of tablespoons of your favourite curry powder.
Spice up your soup by adding a dash of cayenne pepper or red pepper flakes.
Swap out the white potatoes for sweet potatoes.
Add some cooked chickpeas at the end for some additional vegan protein.

What to serve with red lentil soup

This is a light and tangy soup you can enjoy for lunch, dinner, or for a filling snack throughout the day. Instead of only serving plain crackers next to it, try a few more colourful options:

Serve with a batch of warm, super quick and easy no yeast flatbread.
Enjoy with a citrusy salad like my Kidney Bean Salad or Cucumber & Avocado Salad.
Serve alongside a vegetable side dish like this Roasted Red Cabbage.
Bake some fresh bread to slice and dip in the soup, like focaccia, sourdough, or wholewheat. Or for a really quick and easy bread option make my No Yeast White Bread, pictured below.
Crumble over some salty vegan feta cheese or vegan parmesan.
Fresh parsley works incredibly well with it if you have some to sprinkle over the top when serving.
Add a swirl of vegan yogurt.

Storing, freezing, & reheating

This Instant Pot Red Lentil Soup reheats incredibly well and tastes better and better over time. Here are the deets on how to store, freeze and reheat:

Storing: Make sure the soup has cooled completely before storing the leftovers. When ready, place in an airtight storage container and stash away in the fridge for up to 5 days.

Freezing: To freeze the soup, keep it in an airtight freezer-safe storage container. It can be frozen for up to 3 months. Leave it to thaw overnight in the refrigerator before reheating.

Reheating: Warm up this soup on the stovetop in a pot over medium-low heat until hot. It can also be reheated in the microwave. The soup may have thickened after being chilled or frozen. Feel free to stir in extra broth or water to get its consistency back. Add ¼ cup at a time while reheating until you’re reached the desired consistency. Make sure it is piping hot before serving.

Hungry for more?

A cold and rainy day calls for more cozy Instant Pot recipes! Warm yourself up with a bowl of any of these delicious options:

Instant Pot Red Lentil Soup