Slow Cooker Lentil Soup with Zip

Hot soup is the perfect antidote to a cold and blustery day (or night.) And if you can make it in the slow cooker, so much the better. This lentil soup has a lot going for it.

• It is simple, yet hearty enough to be a main course at lunch or dinner.
• While I made the soup in a slow cooker, you can make it on the stovetop if you prefer (or don’t have a slow cooker.)
• An easy step at the end provides extra zip that takes this lentil soup from tasty to addictive. The balsamic glaze or reduction is a one-ingredient wonder condiment that takes just 10 minutes to make. You can make it ahead of time and keep the extra to use as a glaze for vegetables or a marinade for fish or poultry.
• It’s healthy, packed full of beans and vegetables. Because it has no meat or diary, the soup is vegan, making it a great dish to serve vegetarians/vegans. Still, it has an almost meaty flavor that will satisfy the most carnivorous of your family and friends.

Part of what makes many soups, including this one, so tasty is a base of onions, carrots, celery, and garlic. I believe in giving those ingredients time to cook (or as the French say, sauté) together with a bit of olive oil before proceeding with the rest of the soup. That step adds a depth of flavor that you won’t notice in the end result – until you omit it.  

Even in slow cooker recipes, I usually prefer to take a few extra minutes with that step. In this recipe, that initial sauté  is two steps: first, onions, carrots, and celery for eight minutes; then garlic, parsley and thyme are added for two more minutes. Ten minutes to add a layer of flavor that improves the final lentil soup – I think that’s well worth the time expended.

Speaking of not cutting corners, this recipe calls for a sweet potato. Although it may seem like a random vegetable to throw into the soup, the sweet potato adds both flavor and substance that will be missed if you don’t include it. 

I used black lentils in this soup. They hold their shape better than brown, yellow or orange lentils. That quality makes the soup more stew-like in the end. If you don’t care about the lentils holding their shape or prefer a more even (almost creamy) consistency, you could certainly use one of the other types of lentils. The small green lentils known as du Puy or French lentils also hold their shape pretty well, but they are typically more expensive than black lentils. Also du Puy or French lentils take less time to cook, so if you use them, adjust the timing accordingly.

Print Recipe

Slow Cooker Lentil Soup with Zip Yum

A thick and delicious lentil soup with zip - from balsamic reduction or glaze added at the end.

Prep Time

15 minutes

Cook Time

250 minutes

Servings

Ingredients

• 3 tablespoons olive oil
• 2 cups chopped onion carrots, and celery
• 2 teaspoons finely diced garlic 3-4 cloves
• 1/4 cup finely chopped parsley
• 1 teaspoon dried thyme
• 1 1/2 cups black lentils
• 1 large sweet potato cut into 1/2-inch cubes (about 2 cups)
• 2 tablespoons tomato paste
• 4 cups vegetable broth
• 2 cups water
• 1-2 leaves bay 1 large or 2 small
• 2 teaspoons salt or less if your vegetable broth is salty
• Freshly ground pepper
• 1-2 tablespoons balsamic reduction or glaze

Prep Time 15 minutes Cook Time 250 minutes Servings Ingredients 3 tablespoons olive oil 2 cups chopped onion carrots, and celery 2 teaspoons finely diced garlic 3-4 cloves 1/4 cup finely chopped parsley 1 teaspoon dried thyme 1 1/2 cups black lentils 1 large sweet potato cut into 1/2-inch cubes (about 2 cups) 2 tablespoons tomato paste 4 cups vegetable broth 2 cups water 1-2 leaves bay 1 large or 2 small 2 teaspoons salt or less if your vegetable broth is salty Freshly ground pepper 1-2 tablespoons balsamic reduction or glaze

Instructions

1. Heat the olive oil in a large pan.
2. Add the chopped onions, carrots, and celery and sauté them for about 8 minutes, stirring frequently. The onions should be golden/transparent at the end, but not browned.
3. Add the garlic, parsley, and thyme to the vegetables and continue to sauté the mixture for another 2 minutes, stirring until well combined.
4. Move the mixture to a slow cooker. Add the lentils, sweet potato, tomato paste, broth, water, and bay leaves.
5. Cook the soup in the slow cooker for 4 hours on high.
6. Just before serving, add the salt, pepper, and balsamic reduction or glaze. Start with 1 tablespoon of the reduction or glaze, adding a second tablespoon if you like it slightly tangier and sweeter.

Recipe Notes

To cook the soup on the stovetop, use a large pot instead of a slow cooker. Bring the soup to a boil and simmer until the lentils and sweet potatoes are soft.

Share this Recipe

Other hearty soups you might enjoy:

Mushroom Barley Soup

Vegetable Soup

Vegetable Soup with Portabello Mushrooms

Provencal Soup Au Pistou