Chop vegetables.

Heat olive oil in a soup pot. Add the vegetables, stir to coat with the oil, and let cook 5 minutes. Add ground cumin, let cook about another 5 minutes, until onion is softened.

Wash lentils, and add them to pot. Add broth, and bring to a boil. Lower the heat until the soup comes down to a simmer.

Let simmer 45 minutes to an hour.

Serve. Add about a teaspoon of wine vinegar, or to taste, to each bowl.