Some recipes are worth remembering rather than looking up, and this is one of them. Onion, carrot, sweet potato, garlic, a bag of lentils and a tin of tomatoes. Make it twice and you will never need to read it again, which is really the point of a recipe like this.
It is filling in the way that soup is not always filling. Brown lentils hold their shape, so you get something to chew rather than a smooth bowl that leaves you looking in the cupboard an hour later. It costs very little, it uses almost nothing from the fridge, and it is better on the second day.
Ingredients
- 1 tbsp olive oil
- 1 onion, diced
- 2 carrots, diced
- 300 g sweet potato, peeled and diced into approximately 1.5 cm pieces
- 3 garlic cloves, crushed
- 1¼ cups (250 g) dried brown or green lentils, rinsed
- 1.5 L vegetable stock
- 1 x 400 g tin diced tomatoes
- 2 tsp dried mixed herbs, or 1 tsp each dried thyme and oregano
- 1 bay leaf, if available
- 2 large handfuls baby spinach or shredded kale, optional
- Half a lemon
- Salt and plenty of pepper
Method
- Heat the oil in a large pot over medium heat. Add the onion and carrot and cook for approximately six to eight minutes, stirring now and then, until softened. This first step is worth not rushing. It is where much of the flavour comes from.
- Add the garlic and diced sweet potato. Cook for approximately one to two minutes, until you can smell the garlic.
- Add the lentils, vegetable stock, herbs and bay leaf. Bring to the boil, then reduce to a steady simmer.
- Simmer uncovered for approximately fifteen minutes. The lentils will still be firm at this stage, which is correct.
- Add the tin of tomatoes. Continue simmering for approximately twenty to twenty five minutes, until the lentils are tender, the sweet potato is cooked through and the broth is naturally thickened but still clearly soup. Adding the tomatoes at this point rather than at the start matters, because the acid in them can slow the lentils down and they can stay stubbornly hard if the two go in together.
- Add the spinach or kale if using and cook until wilted. Remove the bay leaf.
- Season with salt and plenty of pepper. Finish with the lemon juice and taste again. Lentils absorb a surprising amount of salt, so a soup like this almost always needs more than you first give it, and the lemon lifts the whole pot. If the soup is thicker than you like, adjust it with a little hot water.
It will thicken further as it sits and again overnight, so expect to add a splash of water when you reheat it.
A simple swap. Red lentils instead of brown. They collapse as they cook, so you will get a smoother, thicker soup rather than a chunky one, and the whole thing will be ready about ten minutes sooner. Both versions are good. They are just different soups.
Make it your own. Add diced potato, frozen peas, extra leafy greens or a tin of chickpeas. A teaspoon of ground cumin and a teaspoon of smoked paprika added with the garlic take it somewhere warmer and slightly smoky. Chilli flakes add heat, while parsley or a little lemon zest at the end keeps it fresh.
To serve. Crusty bread and a drizzle of olive oil is the whole meal. A spoonful of hummus stirred into the middle of the bowl is unexpectedly good and turns it into something richer.
Why this soup is useful
It earns its place for reasons that have nothing to do with being clever.
It uses vegetables that keep. Onions, carrots and sweet potatoes all sit happily in a cupboard or a crisper drawer for a fortnight, so this is available on the Thursday when everything fresh has gone. The lentils need no soaking and cook from dry in the same pot, which means there is nothing to plan the night before.
It also makes a real meal rather than a starter. A bowl of this with bread is dinner, and that is not true of every soup.
And it is forgiving. Too thick, add water. Too thin, simmer a bit longer. Slightly bland, more salt and more lemon. There is no stage at which it can go badly wrong, which makes it a good one to learn on.
Make it once, use it twice
This makes a generous four servings, and it is genuinely better the next day once the lentils have had time to sit in the broth.
Cool it reasonably quickly and keep it in the fridge for up to three days. It reheats gently on the stove with a splash of water. It also freezes well, so if there is more than you will get through, put half into a container before anybody eats any, and you have a dinner waiting for a week that needs one.
Leftover soup that has thickened a great deal overnight is also very good spooned over a jacket potato, which is not what it was designed for but is worth knowing.
Keep these on hand
None of this needs a special shop, but it does need a few things to be in the house already.
Dried brown or green lentils, which keep for a year in a jar. Tinned tomatoes. Stock, whether cubes, powder or liquid. Onions and garlic. Carrots and sweet potatoes. Dried herbs. Olive oil, salt and pepper.
That short list also happens to cover a great many other dinners, which is the argument for a small pantry that gets used rather than a large one that mostly waits. There is more on which staples earn their keep in 10 Plant-Based Pantry Staples That Make Everyday Meals Easier, and if you have lentils and tinned tomatoes in the cupboard, Pantry Tomato and Lentil Pasta is the other thing worth knowing how to make with them.