Preheat your oven to 325°F (165°C).

Rinse the turkey under cold water and pat it dry with paper towels. Place it in a roasting pan.

Melt the butter and brush a generous amount over the turkey. Season with salt and pepper to taste.

In a large skillet, melt remaining butter over medium heat. Add diced celery and onion; cook until softened, about 5-7 minutes.

In a mixing bowl, combine the sautéed vegetables, cubed bread, sage, thyme, parsley, and salt. Mix well.

Gradually add the broth to the bread mixture until it is moist but not soggy.

Stuff the turkey with the dressing mixture. Secure the opening with kitchen twine or toothpicks.

Cover the turkey with aluminum foil and roast in the preheated oven for 2.5 hours. Remove the foil during the last 30 minutes to brown the skin.

Insert a meat thermometer into the thickest part of the thigh; it should read 165°F (74°C) when fully cooked.

Once cooked, remove the turkey from the oven and let it rest for at least 20 minutes before carving.

To make the gravy, pour the turkey drippings into a saucepan, sprinkle the flour over it, and whisk until smooth. Cook over medium heat until thickened, about 5-7 minutes.