Combine the vegetable stock, salt, brown sugar, peppercorns, allspice , and ginger in a large stockpot over medium-high heat.
Stir occasionally to dissolve solids and bring to a boil.
Then remove the brine from the heat, cool to room temperature, and refrigerate.
Early on the day or the night before you'd like to eat:
Combine the brine and ice water in a 5-gallon bucket.
Place the thawed turkey (with innards removed) breast side down in brine. If necessary, weigh down the bird to ensure it is fully immersed, cover, and refrigerate or set in cool area for 8 to 16 hours. (If you do not have room in the refrigerator you can use a large cooler. Put the bucket in the cooler and surround it with A LOT of ice).
Preheat electric roaster to 325 degrees F. Remove the bird from brine and rinse inside and out with cold water. Discard the brine.
Place the bird on roasting rack inside the roaster and pat dry with paper towels.
Roast the turkey until the internal thigh temperature is 160 degrees.
Remove the turkey from the roaster and baste the turkey with the melted butter.
Broil in oven on the lowest rack of the oven just until the turkey turns brown and the skin is crispy.
Note: Turkey should be removed when the internal temperature of the internal thigh is 170 degrees. Remove from oven, cover, and let rest for 15 minutes until the internal temperature is 180 degrees.