It's best to soak lentils before cooking them. Soak them for at least one hour, even better if it's 4 hours. You can also soak them overnight.
Let's start by preparing all the ingredients. Chop onions and garlic. Peel and cut carrots into small pieces. Clean leek and slice it into circles. Wash spinach and chop it roughly. If your spinach leaves are small, there's no need to chop them, otherwise it's nice to make them a bit smaller.
On to cooking. Warm-up olive oil in a large pot. Sautée onions for a few minutes along with carrots. When carrots start softening and onions start getting a bit of a brown colour, add curry powder, cumin, and garlic. Sautée for another 2 minutes, then add leek. Sautée a bit more until leek softens a bit.
Then add soaked and strained lentils and tomato pieces. Add salt, stir well, cover with a lid and let simmer for 15-20 minutes. The time it will take for lentils to soften depends on how long they've been soaking. Green lentils take up to 45 minutes to soften, but if soaked, it can only take 15-20 minutes. Soaking also helps with digesting them and eliminates bloating and gases.
When lentils are cooked, add spinach and stir it in.
A minute or two later, when spinach softens, add freshly ground black pepper. I add at least 2 tsp, but it really is up to you how much you add as black pepper is a bit spicy. Then squeeze a bit of lemon juice in, too. Stir and voilá - your soup is ready!
You can serve this soup on its own or add some pitta bread. You might want to go with rice, amaranth, bulgur, or quinoa as a side dish. A fresh salad also fits well with this meal.
