The Ultimate Turkey Dinner Leftovers Soup

Name: The Ultimate Turkey Dinner Leftovers Soup
Ingredients: 2½ cups leftover stuffing; ½ cup finely grated parmesan cheese; ½ cup grated mozzarella; ¼ cup heavy (35%) cream; 2 Tbsp. canola oil; 2 yellow onions, diced; 6 cups turkey broth (or chicken broth); 2 cups leftover mashed potatoes; ½ cup leftover gravy; 1 Tbsp. apple cider vinegar; 1 tsp. dried rosemary; 1 cup chopped leftover carrots (or other winter vegetable like parsnips, acorn squash, or butternut squash); 1 cup finely chopped leftover cooked turkey meat; Salt