Heat olive oil in a large saucepan over medium heat.
Add the diced onion, carrot and celery and fry until onion is soft - about 5 minutes.
Next, add the spices, garlic, ginger and lentils, and stir for 30 seconds until fragrant.
Add the tin of tomatoes and water, and salt and pepper.
Bring soup to the boil, then simmer on low-medium, uncovered, for 20-30 minutes or until thick.
Season with extra salt and pepper and serve.
Notes
Heavy-Based Saucepan - Use a large, heavy-based saucepan, not a cast-iron pan, as the lentils stick to the bottom of the pan. Stirring the Soup - stir the soup occasionally so the lentils don't stick. Serving Suggestion - serve with a dollop of Greek yogurt and some freshly chopped parsley. Nutrition Info - doesn't include any additional toppings like the yogurt.