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.