Remove the turkey from the fridge one hour before roasting. Remove the giblets and neck. Rinse the turkey, pat dry and allow to come to room temperature.
To make the chimichurri butter, place the parsley, scallions, garlic, and oregano in the food processor. Pulse until finely chopped, stopping to scrape down the sides of the bowl as necessary.
Add the butter and the vinegar, mix well to combine, making sure the butter is smooth and the herbs evenly mixed throughout, place in a bowl and add the red pepper flakes and olive oil. Mix well and set aside. Rub the chimichurri butter all over the turkey.
Preheat the oven to 450 degrees F. Position a rack in the lower third of the oven. Place the turkey in a large roasting pan. Pour 3 cups of chicken broth into the bottom of the roasting pan. Place the turkey in the oven and turn down the heat to 350°F. Cook for about 3 hours (until the turkey registers 160 F. on a meat thermometer), baste the turkey with the drippings about 4 times throughout cooking.
Remove the turkey from the oven, transfer the turkey to a baking sheet or platter, tent loosely with foil and let rest for about 30 minutes before slicing.