Thoroughly pick over and wash the lentils. Peel and dice the potatoes. Set them aside for later.
Heat a large pan over medium heat. Add 2 tablespoons of olive oil.
Once the oil is hot add the diced onion, celery and carrot with a pinch of salt. Cook until the carrot has begun to soften and the onion is translucent. Around 6 minutes.
Add the pastes and spices, red pepper paste, tomato paste, ground cumin, paprika, salt, and cracked black pepper. Stir everything to coat the vegetables in the pastes and spices. Continue to cook for a further 1 minute.
Now add the potato, red lentils and the water, mix everything together then bring to a boil. Once boiling turn the heat down to a simmer and cover the pan. Simmer for 20 to 25 minutes until the red lentils are soft and falling apart.
Turn off the heat and using either a hand blender or by transferring into a blender, blend the soup until smooth.
If the soup seems too thick you can thin it out with some water.
Serve hot with a garnish of parsley, sumac and Aleppo pepper. Squeeze over a wedge of lemon before eating.
Notes
Leftovers can be kept in the fridge for a couple of days. Reheat in a pot using a whisk to remove any lumps. Soup will turn solid when kept in the fridge but will return to liquid when heated up.