Red Lentil Soup

Last updated on: September 14, 2026

Jump to Recipe

This high-protein red lentil soup is proof that a handful of cheap supermarket ingredients can turn into something properly satisfying.

Red lentils cook down until soft and creamy, naturally thickening the soup without needing cream, milk or a blender. Add onions, carrots, celery and a little tomato purée and you’ve got classic, comforting soup with very little faff.

Each serving contains around 13g of protein and 217 calories, with red lentils providing the bulk of the plant-based protein. That makes it a useful option for healthy lunches, meal prep or lighter dinners when you’re trying to increase your protein without piling on the calories.

You only need a large saucepan, a chopping board and a knife. No soup maker, blender or suspicious gadget purchased during lockdown required.

And if soup season is basically a year-round event in your house, have a nosey at my collection of high-protein soup recipes for more ideas.

Why you’ll love this high-protein recipe

• 13g protein per serving from red lentils – impressive work from something so small and orange.
• Only 217 calories per bowl, making it useful for lighter lunches or weight-loss-friendly meal planning.
• Cheap ingredients you can find in virtually any UK supermarket.
• Naturally vegan when made with vegetable stock.
• Excellent for batch cooking because it reheats beautifully and freezes well.
• No blender needed – the lentils break down and create a thick, comforting texture all by themselves.

Red Lentil Soup Main Ingredients

Onions. You can use white or red onions but I think using red just helps the final dish look a bit more interesting. Some people often use a leek instead of an onion.

Carrots. Carrots add a natural sweetness and vibrant colour to the soup. They're also a great source of vitamins, including beta-carotene, which is good for eye health.

Celery. Pretty much a fundamental ingredient in many stews, casseroles and soups.

Tomato Puree. I was surprised about this one when I got the recipe. But who am I to try and change a Granny's lentil soup recipe?

Red Lentils. Red lentils are the star of the recipe, chosen for their quick cooking time and ability to break down, thickening the soup naturally. They're an excellent source of plant-based protein and fiber. Make sure you rinse them first.

Stock. Stock forms the liquid base of the soup, providing depth and richness. Usually made with ham or chicken stock (both of which give it more flavour) but if you're following a vegetarian or vegan diet, use vegetable stock instead.

Black Pepper. I think this is a key ingredient. Go to town and season very liberally.

How to Make Red Lentil Soup

Serving & Storage

To Store

Let the lentil soup cool before transferring it to an airtight container. Keep it in the fridge for up to 4 days.

It will thicken as it sits because lentils are thirsty wee things, so don't panic when tomorrow's lunch looks considerably sturdier than today's.

To Reheat

Reheat gently in a saucepan over a medium heat until piping hot, stirring regularly.

You can also microwave individual portions. Add a splash of water or vegetable stock before reheating if the soup has become too thick.

To Freeze

Allow the soup to cool completely, then portion it into freezer-safe containers.

Freeze for up to 3 months. Defrost overnight in the fridge before reheating, adding a little extra stock or water if required.

Serving suggestions

Serve the soup exactly as it is for a simple 217-calorie lunch, or bulk it out depending on your goals.

Try it with wholemeal bread, toasted pitta, a baked potato or a simple sandwich. For extra protein, add a spoonful of Greek yoghurt if you don't need the recipe to remain vegan, or top it with roasted chickpeas, pumpkin seeds or a little crumbled feta.

Variations & tips

• Boost the protein further: Stir through cooked chickpeas, cannellini beans or shredded chicken. The latter obviously means we're waving goodbye to the vegan badge.
• Use chicken stock: If you're not vegetarian, chicken stock gives the soup a slightly richer flavour.
• Add some spice: Cumin, smoked paprika, chilli flakes or curry powder all work brilliantly with red lentils.
• Don't rush the vegetables: Giving the onions, carrots and celery their full 10 minutes at the beginning develops much more flavour than chucking everything into the pan at once.
• Adjust the thickness: This recipe becomes properly thick once cooled. Add extra stock if you prefer a looser soup.
• Want it completely smooth? You absolutely can blend it with a stick blender, although the lentils break down so thoroughly that I don't think it really needs it.

High Protein Red Lentil Soup

5 Stars 4 Stars 3 Stars 2 Stars 1 Star

4.8 from 6 reviews

Print Recipe

Pin Recipe

Discover the warmth and comfort of homemade high protein soup recipe: red lentil. Dive into this hearty, nutritious dish packed with flavours, perfect for cosy nights or healthy lunches.

• Total Time: 1 hour 5 mins
• Yield: 4 1x

Ingredients

Units MUS Scale 1x2x3x

• 1 tbsp. olive oil
• 2 onions, chopped
• 2 carrots, chopped
• 2 sticks celery, chopped
• 1 tbsp. tomato puree
• 230g red lentils, rinsed
• 1.2L vegetable stock
• Black pepper, about 20 grinds

Cook Mode Prevent your screen from going dark

Instructions

Heat oil in a large pan on medium heat. Add the vegetables and cook for 10 minutes until they are softened.

Stir in tomato puree and lentils and pour in the stock. Season generously with black pepper and bring to a boil.

Reduce heat, cover the pan and simmer for 45 minutes until the lentils have completely broken down.

• Author: Scott Baptie
• Prep Time: 10 mins
• Cook Time: 55 mins
• Method: Hob
• Diet: Low Calorie

Nutrition

• Serving Size: 1
• Calories: 217
• Fat: 5g
• Carbohydrates: 18g
• Protein: 13g

Recipe Video

Frequently Asked Questions (FAQs)

Can I use other types of lentils instead of red lentils?

Yes, you can use other lentils like green or brown, but keep in mind that they have a longer cooking time and won't break down as much as red lentils.

Is this soup suitable for vegetarians or vegans?

Yes, this soup is vegetarian and vegan-friendly as it uses vegetable stock and plant-based ingredients.

Can I make this soup in a slow cooker?

Absolutely! Combine all ingredients in the slow cooker and cook on low for 6-8 hours or on high for 3-4 hours.

Is red lentil soup gluten-free?

Yes, this soup is naturally gluten-free, but always check the labels of your vegetable stock and other ingredients to be sure.

Can I add meat to this soup?

Sure. Many people cook this with a ham hock in it but, you can add cooked chicken, beef, or lamb for extra protein.

Can I blend this soup for a smoother texture or should I leave it chunky?