Into a large, deep skillet over medium-high heat, add the butter. When the butter is melted, add the carrots, celery, and onion. Cook, stirring frequently for 3 minutes, until slightly softened.
Add the cauliflower and mushrooms then season with poultry seasoning, salt and pepper. Continue cooking for 5 minutes, until vegetables are tender.
Sprinkle with parsley, rosemary, and sage.
Pour in the chicken-style broth and stir gently to combine.
Cook, stirring frequently, for 10 minutes more, or until the liquid is absorbed.
Adjust seasoning to taste and serve hot.