In a large pot, cook the onion in the olive oil over medium heat until translucent. Add the sausage and cook until it’s brown and cooked through.

Add the carrots, potatoes, tomatoes, mushrooms, chicken broth, lentils, and seasonings to the pot. Cover and bring just to a boil. Lower the heat and simmer gently, partially covered over medium low heat, for about 20 to 25 minutes, or until the lentils are cooked and the vegetables are tender. Serve warm.