A simple and delicious curried butternut squash lentil soup that is as easy to make as it is delicious. Packed full of plant-based protein, at 20 grams of protein and only 280 calories per serving.
From chickpeas to black beans, to lentils and peas, to peanuts to soybeans. Legumes are one of the best foods we can feed our body, but often one of the foods we don’t eat enough of. They have a complex nutrient profile, offer plant-based protein, iron and zinc, and they are one of the most sustainable sources of protein we have access to. Clients tell me that a lacking in confidence in the preparation of legumes that is a large factor in their limited consumption. This is one of my favourite recipes for introducing clients to cooking with dried lentils. This Curried Butternut Squash Lentil Soup really is fail-safe and will take 35 minutes cooking time tops.
“Legumes are low glycemic index (GI) and can help to stabilize blood glucose levels. They are also a great source of plant-based protein, iron and zinc.”
Health Benefits of Lentils
Lentils and Protein
Legumes are one of the best sources of protein in the plant. A 1 cup serving of cooked lentils contains around 17g of protein, which is as much protein as 3 eggs or a can of tuna. Proteins are made up of amino acids, and to be a complete protein a food must have all essential amino acids. Legumes are lacking in the amino acid methionine, but are high in the amino acid lysine. Combining legumes with grains, nuts or seeds, as well as squash as is used in the recipe, helps to complete the protein so our body can use the protein efficiently and effectively.
Lentils and Iron
Lentils and other members of the legume family are one of the best sources of iron on a plant-based diet. One cup of cooked lentils can have up to 6 milligrams of iron and one serving of this soup contains a whopping 7.3 milligrams (a 100 gram sirloin steak contains around 2.9 milligrams). Most adult women require up to 18 milligrams of iron per day, while adult men require 8 milligrams. The type of iron coming from plant sources (legumes, nuts, green leafy vegetables, grains) is called non-haem iron and is less bioavailable than iron coming from animal sources (haem iron).
How To Maximise The Absorption of Iron: Vitamin C helps to absorb the iron from non-haem sources more efficiently, so adding some fresh lemon juice to a lentil soup (heat degrades Vitamin C) is a great way to ensure maximum iron absorption is happening. Pre-soaking your lentils can also help, see more information in notes below.
Lentils and Zinc
Zinc is an essential nutrient that many of us are not getting enough of. If you are following a plant-based diet, lentils and other legumes may be one of your top source of zinc (some of the highest sources of zinc are beef and oysters). Men need at least 11 milligrams of zinc per day, while women need 8 milligrams per day.
How to Maximise The Absorption of Zinc: Zinc, along with iron and other minerals, is better absorbed from grains and legumes with some pre-soaking, fermentation or germination. See below for more information on pre-soaking, and my post on maximising zinc absorption here.
Side Effects of Eating Legumes
Legumes and Gas
Aside from a lacking in confidence in preparing lentils and other legumes, the second most common reason clients tell me they avoid them is because they can cause excess gas. Gas is formed when the bacteria in the colon feast on the fibres in the food, and one of the byproducts of the feasting is well… gas. Beans contain a type of fibre called oligosaccharides, which like all fibres is indigestible. The fermentation process in the colon that results from consuming too much of this type of fibre can create excess gas in those that are more susceptible.
Some tips for taming the gas producing compounds in legumes:
- Mix 1/8 teaspoon of baking soda or a spoon of vinegar into the soaking water. Soak legumes for eight to 10 hours.
- Rinse legumes thoroughly and don’t cook legumes in the water in which they were soaked because it contains the gas-causing sugars.
- Slow cook legumes in a crockpot for several hours.
- Drain and rinse canned legumes; this will significantly reduce the gas-producing oligosaccharides.
- Add legumes to the diet in small amounts in the beginning until you get used to it.
Legumes and Irritable Bowl Syndrome
If the gas persists, is excessive, or is accompanied by abdominal pain and diarrhoea/constipation then it is suggested you speak to your doctor or Registered Dietitian about the possibility of Irritable Bowel Syndrome and consider the low-FODMAP approach.
“Anti-nutrients” in Legumes
Some popular diet books are critics of legumes, mainly because of the ‘anti-nutrient’ phytic acid. Phytates are a compound in legumes, as well as grains, nuts and seeds, that can bind to the minerals in the food (and other food consumed with it) making them less absorbed by the body. Soaking, sprouting or fermenting your legumes helps to decrease phytic acid, making the minerals more bioavailable to the body. See below for more information on soaking legumes.
Sustainability of Legumes
Legumes get an A+ for sustainability. Legumes have the unique ability to fix nitrogen which could play a big part in decreasing our dependence on commercial fertilisers and thus decreasing greenhouse gas emissions. This feature also makes the rotation of crops with legumes especially suitable for organic production where the use of chemical fertilisers is forbidden.
Decrease Reliance on Animal Proteins
We know that beef is one of the highest emitters of greenhouse gasses and produces 13 times more carbon dioxide equivalents compared to legumes. Replacing one meat dish with one lentil dish per week can drastically reduce our carbon footprint.
Eating On A Budget
Lentils are very cost effective. Other countries are doing it right, and their high consumption of legumes helps to decrease the cost of food while still providing nourishing meals. Think daal in India, tempeh in Indonesia, hummus in the Middle East, tofu in China or refried beans in Latin America. One serving of lentils can cost less than $1, whereas the same portion of meat can cost upwards of $4.
Tips On Making Butternut Squash Lentil Soup
Cutting Butternut Squash
Some feedback from this recipe has been that some instructions on how to cut a butternut squash would be helpful. The most important tip is to make sure you have a sharp knife. I always remind people that a dull knife is more dangerous than a sharp knife.
Cutting Butternut Squash
- First, lay the squash lengthwise on a cutting board and trim off both ends,
- Slice the squash in half, flip the smaller half so the flat side is against the cutting board and carefully shave the skin off using your knife on an angle. Continue shaving the squash, spinning it as you go, until all the skin is removed. You will lose a little bit of flesh but that is OK,
- Flip the squash back on its side and cut into rounds, about 3/4″ wide,
- Flip back over so the flat side is against the cutting board, and stack the rounds up. Chop into 3/4″ cubes,
- Repeat process with the other side. This side will have seeds in the middle, so instead of cutting into cubes, trim the squash flesh off from around the seeds ensuring that all the pieces are similar in size to the first batch.
Making Homemade Stock
Going forward, a good strategy to make sure you always have some good quality vegetable stock on hand is to save your ends and peels of certain stock vegetables, this includes onion, garlic, carrots, celery and leeks. Save these pieces in a container in your freezer, and when it is full simply add them to a large stock pot, add some salt and whole black pepper and boil for about an hour or longer or until you are satisfied with the flavour. Strain and store the stock in your freezer in 1.5L yogurt containers, which is the perfect amount for this soup.
Notes On Recipe for Squash Lentil Soup
Red lentils are the best type of lentil to use in this dish as the break apart easily, adding to the overall texture and creaminess of the dish. They also take the least amount of time to cook out of all the lentils. If you have green lentils or split peas on hand you could definitely use them. Add them to the soup at the same time as the stock to account for the longer cooking time. The outer fibre of the green lentils is more pronounced, which will result in a less creamy consistency.
Red lentils do not need to be pre-soaked and can usually be added straight into the recipe without any pre-preparation. I always suggested washing your lentils, as good quality local lentils will often have a few tiny pebbles in the mix.
Ideally, any lentil or legume should be pre-soaked, and this is to help remove some of the phytic acid or phytates which have been referred to as ‘anti-nutrients’. Soaking helps us to better access minerals including zinc and iron in the lentils and any legume, and this is especially important for those following a plant-based diet. For more information on maximizing absorption of zinc see my post here.
There is no defined length of time necessary for pre-soaking lentils and other legumes. As a general rule, I try to aim for at least 12 hours for smaller legumes and 24 hours for larger beans. I would say 4 hours would be a minimum for smaller lentils, including these red lentils. Remember, eating lentils that haven’t been pre-soaked is absolutely fine; lentils are one of my top ‘superfoods’ and still offer many health benefits even if they haven’t been pre-soaked. For more information on how to prepare lentils see my post How To Cook Lentils.
I also like to use Kabocha Squash in this recipe, which also results in a nice creamy flavour. Sweet potato and yam also work well, or a combination of yam and butternut squash. Acorn squash lentil soup is also very tasty.
If you are are not a fan of curry, you can opt to leave the curry powder, cumin and coriander out. The onion and garlic offer enough flavour that the recipe does not need the extra spices. Additionally, I love making a spicy butternut squash lentil soup by adding more chillies.
Chunky or Blended
I can never decide on my favourite way to serve this soup. After the butternut squash lentil soup is finished cooking, you have the option of taking a potato masher or pastry cutter and mashing up the squash chunks which leaves with a nice hearty chunky butternut squash lentil soup. Alternatively, you can use a stick blender to puree the soup to form a creamy consistency. A blender can be used as well, just make sure it has a steam vent when blending hot liquids.
My Other Favourite Lentil Soup Recipes
If you have checked out some of my other recipes you probably know I’m a big fan of lentil soups. This is one of my favourite recipes for introducing legume-skeptics to the world of lentils, as the red lentils break apart nicely and they are barely recognizable. Some of my other favourites include Easy Lentil Soup with Kale, Mixed Lentil and Bean Winter Warming Soup and Vegetarian Greek Lentil Soup with Lemon and Feta.
Did you make this Butternut Squash Lentil Soup recipe? Please let me know how it turned out for you! Share it on Pinterest and leave a comment below. I would love it if you shared a picture of your recreation on Instagram so I can take a look, and be sure to tag me @theconsciousdietitian.
Curried Butternut Squash Lentil Soup
- 1 tbsp olive oil
- 1 medium onion diced
- 2 cloves garlic minced
- 1 small red chili minced (optional)
- 1 tbsp curry powder
- 1 tsp cumin powder
- 1 tsp coriander powder
- 1/2 tsp turmeric powder
- 800 g butternut squash skinned, de-seeded and cut into 1 1/2" cubes (about 4 cups)
- 1 1/2 cups red lentils dry
- 6 cups vegetable stock organic
- 1 lemon
- natural yogurt optional
- Rinse red lentils. This is important to avoid biting into any tiny little pebbles.
- Heat olive oil in large soup pot over medium heat. Add onions and gently fry until translucent, about 3 minutes. Add garlic, chilli and all spices and fry until fragrant, usually another 30 seconds.
- Add squash and reduce heat. Cover pot and let squash cook for about 10 minutes, stirring occasionally. Once squash has softened add the vegetable stock and bring to a boil.
- Next add the red lentils to the soup mix, let simmer for about 15 minutes or until the lentils have completely broken apart. Check to make sure the squash is nice and tender. Add more water or stock if the soup gets too thick.
- Now for decision time, do you like your soup chunky or blended? Sometimes I like to mash my soup with a potato blender, and sometimes it is nice to have a blended soup. If you have a hand held stick blender this is usually the easiest to use.
- Serve with a squeeze of lemon juice. This is the secret ingredient. Not only does it make the soup taste great, but it also helps you to absorb the iron from the lentils more efficiently. I also like to eat mine with a dollop of natural yogurt.
Decrease the Sodium: Make your own vegetable stock with leftover onion skins, leek tops and carrot tips.
Make it Vegan: Omit the yogurt, and use a cashew cream instead.
Rachel Dickens, The Conscious Dietitian, is a Registered Dietitian and Certified Diabetes Educator. She graduated with her Masters in Nutrition and Dietetics in 2010 from Griffith University. She strives to provide evidence-based nutrition information with a focus on plant-based nutrition, and share some of her favourite seasonal recipes and sustainable eating tips.