Instructions:
Preheat oven: Preheat your oven to 350Β°F (175Β°C).
Prepare turkey: Rinse the turkey, remove giblets, and pat dry.
Season turkey: Rub the softened butter and olive oil over the turkey, then season with salt, pepper, garlic powder, onion powder, thyme, and rosemary.
Stuff cavity: Stuff the turkey cavity with the quartered onion, smashed garlic, chopped carrots, and chopped celery.
Prepare bag: Place the flour in the oven bag and shake to coat the inside.
Place turkey in bag: Carefully place the seasoned turkey into the oven bag.
Seal and vent bag: Close the bag, leaving some space for air. Cut 4-5 small slits in the top of the bag to allow steam to escape.
Roast turkey: Place the roasting pan with the turkey in the preheated oven. Roast for 2 to 2 Β½ hours, or until the internal temperature reaches 165Β°F (74Β°C).
Rest turkey: Let the turkey rest in the bag for 15-20 minutes after cooking.
Carve and serve: Carefully cut open the bag and carve the turkey.
Enjoy your delicious roasted turkey!