Combine lentils with stock, add bay leaves and bring to a boil on high heat.
Meanwhile, using a mini food chopper, chop carrot into pretty small pieces and add to the soup. Repeat this process for celery ribs and tomato. If you do not own a food chopper - get one! But seriously, if you do not have one, just chop the veggies with a knife.
Once soup starts boiling, add salt and pepper, reduce heat to medium-low, cover with lid, and let it cook for about 45-50 minutes.
After 50 minutes have passed, turn off the heat, add parsley, and stir. Let it rest for 10 minutes before serving.
Serve with a spoonful of sour cream. Enjoy!