Wash the lentils thoroughly in a colander until the wash water no longer becomes cloudy. Drain the lentils.
Peel the onions and cut into small cubes. Peel garlic and chop finely.
Heat the olive oil in a large saucepan and sauté the onions and garlic until translucent. Add about 10 cm of tomato paste from the tube and 10 cm of harissa from the tube to the onions and stir everything well. Then add the drained lentils and sweat for about 2 minutes.
Deglaze with plenty of water - approx. 2 liters. Salt and bring to a boil over high heat with the lid closed. As soon as the water bubbles, reduce the temperature to a low flame. Let the lentils steep until the lentils are completely swollen. Add more water. Season to taste with salt and pepper. Do not season too salty. If you like it spicy, you can season the soup with sriracha.
After about 35 minutes, finely puree the soup with a hand blender.
The soup tastes best if you leave it in the pot overnight and reheat it the next day. When warming up, the soup must be stirred thoroughly, otherwise the lentil paste will settle on the bottom of the pot.
Serve with lemon wedges and drizzle the lemon into the soup to eat.
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