In a saucepan, on medium heat, put the lentils and onions with 9 cups of water.

Stir lentils and onions from time to time. When the water starts to boil, lower the heat and cover the saucepan. Leave to cook for 40 min.

When lentils are cooked, add in the salt, cumin and black pepper and stir. Remove pan from heat.

Pour the lentil and onion mixture in a food processor and blend until you get a smooth and thick mixture.

Pour back the mixture in the saucepan. Put on medium heat. Stir the ingredients while adding the olive oil and leave it to simmer for 5 more minutes.

Serve the lentil soup immediately.

A tasty addition to this delicious soup would be a squeeze of lemon and some roasted pita bread pieces that you sprinkle on top of the soup once it's served.

Note: Depending on the type of lentils, you might need more or less water to cook. Small-sized lentils require more water.