First, gather your ingredients. Peel and dice the onion, celery, garlic and carrots. For a chunky soup, cut the vegetables into small pieces. If you want a smoother soup, save time by cutting bigger chunks and blending later.
Heat the olive oil in a saucepan or casserole dish/Dutch oven. Add the chopped onion and celery. Sauté gently over a medium heat for about two minutes.
Add the garlic and continue to cook for a further three minutes or so, until the onion is translucent and just starting to turn golden, and the fragrances are released.
Add the spices and cook gently for a further a minute or so. You want to release the flavour, but not burn the spices.
Stir in the carrots.
Add the lentils, tomato puree and stock, and stir well.
Bring to a simmer. Put the lid on and turn the heat right down. Leave the soup to cook for about 30 minutes, until the lentils are mushy and the carrots soft.
Adjust the texture as you prefer. If you like your soup smoother, mash with a potato masher, or blend to the texture you want. You can add more stock or water to thin the soup if you choose.
Add the chopped coriander and lemon zest, and stir in. Season to taste.
Serve garnished with more coriander and some pumpkin seeds, or with a little natural yogurt.
