1 can (19 ounces) petite-cut tomatoes (with liquid)
1 tablespoon balsamic vinegar or a splash of red wine
2 tablespoons dried Italian seasoning or 1 teaspoon each of dried oregano and dried basil
1 can (19 ounces) lentils, drained and rinsed
2 tablespoons minced fresh parsley (optional)
Heat olive oil in a large soup pot over medium-high heat. Add onions, carrots, celery and garlic. Cook and stir until vegetables begin to soften, about 3 minutes. Add mushrooms and continue to cook until mushrooms are tender, about 5 minutes.
Stir in marinara sauce, tomatoes with their liquid, vinegar and Italian seasoning. Bring mixture to a boil. Reduce heat to low, cover and simmer for 15 minutes. Ass lentils and cook for 5 more minutes. Remove from heat and stir in parsley – if using. Serve over hot pasta.