This is a filling, hearty soup that is very easy to make!
Heat olive oil in a large saucepan over medium heat; cook and stir onion and garlic until onion is translucent, about 5 minutes.
Stir in carrot and celery; cook, stirring often, until vegetables are tender, about 8 more minutes.
Stir in tomato paste, crushed red pepper, cayenne pepper, salt, and black pepper; mix in chicken stock and lentils.
Bring soup to a boil and reduce heat to low; simmer until lentils are soft, about 20 minutes.
Per Serving: 217 calories; protein 13.6g; carbohydrates 33.7g; fat 3.5g; cholesterol 0.7mg; sodium 711.3mg.