Reduce the stress of making the gravy while the turkey rests by making it up to 3 days ahead. Amp up the turkey flavor by stirring in any drippings just before reheating and serving.
6 cups low-sodium turkey or chicken stock
3/4 cup dry red wine
1 medium onion, cut into 6 wedges
2 small sprigs rosemary
5 tbsp unsalted butter
1/3 cup all-purpose flour
1/2 tsp Worcestershire sauce
Reserved Turkey Drippings
In a medium pot, combine the stock, wine, onion, and rosemary. Heat to a boil on high. Reduce heat to simmer. Simmer 30–45 min., until reduced to about 4 cups, stirring occasionally. With slotted spoon, discard onion and rosemary. Transfer liquid to a large bowl. Wipe out pot.
In pot, melt the butter on medium. Sprinkle in the flour and cook 3–4 min., until golden, stirring constantly. Slowly whisk in broth mixture and Worcestershire sauce until smooth. Heat to a simmer on high. Reduce heat and simmer 5 min., until thickened, stirring occasionally. Let cool completely and refrigerate for up to 3 days.
When ready to serve, transfer gravy to a pot and heat on medium until hot. Whisk in any turkey drippings from roast turkey. Season with salt and pepper to taste. Serve hot.