Make the turkey sausage by mixing salt, pepper, sage, red pepper flakes, fennel, marjoram, and onion powder with the ground meat in a medium bowl.
Add olive oil and onion to a large pot and stir with a wooden spoon over medium heat for 2-3 minutes until tender and fragrant. Add turkey sausage, stir and cook until browned. Add garlic sautéing a minute more.
Add celery, carrots, and cauliflower, rosemary, smoked paprika, bay leaves, pepper, salt, canned tomatoes, tomato paste, broth, and lentils.
Bring soup to a boil and turn down to a simmer for 20-25 minutes or until lentils are tender.
Stir in red wine vinegar. Adjust salt and pepper to taste. This soup is always better the next day!
