In a pot, combine the lentils, tomato, onion, garlic, carrot, potato, and bouillon cube. Cover the ingredients with water and let the mixture boil for about 30 minutes until all ingredients are cooked.

Remove the pot from the heat and let it cool slightly. Then, blend the mixture with an electric blender until smooth.

Return the blended lentil mixture to the stove. Season with salt, black pepper, cumin, and olive oil. Stir well.

Let the soup heat through on the stove for about 3-5 more minutes.

Pour the soup into serving bowls and serve it hot with lemon slices on the side.