Preheat oven to 400F.
Swirl olive oil over large roasting pan, then add carrots, potatoes, shallots, onion and broth and stir to coat.
Cook in the oven, stirring occasionally, until vegetables are tender and lightly browned, about 1 hour. Remove from oven.
Lower oven temperature to 350F.
Add remaining ingredients (except butter) and mix until thoroughly coated.
Turn into a baking dish sprayed with nonstick cooking spray.
Dot top with butter, if desired, and bake for about 1 hour, or until top is browned and dressing is heated through.
If you use this as a stuffing, it’s plenty for a 12 – 14 pound turkey. Makes about 10 cups, to serve 8 with leftovers.