- Heat a large saucepan over medium-high heat.
- When hot add the oil and onion and sauté the onion until it is brown.
- Meanwhile, put carrots and celery in the bowl of a food processor and process until finely chopped (this took about 10 seconds on speed 6 in my thermomix) - or you can finely chop by hand.
- Add the garlic, cumin, sweet paprika and tomato paste to the onions and stir for a few minutes before adding the chopped carrot and celery along with the red lentils and vegetable stock.
- Bring the soup to the boil, then turn it down to a simmer.
- Place a lid on the pot and cook for 15 minutes.
- It can be served as is, or if you prefer you can use a hand blender to make it a bit smoother (or puree it in your food processor).
- Serve with fresh parsley, chives or coriander.