When creating this recipe, I was thinking about the crispy Peking ducks that hang in the windows of Chinese restaurants, and how hungry they make you feel. We're going to recreate that tasty skin on the outside of our turkey, as well as the flavors that go with it: a little sweet, a little salty, nice and crunchy. (Note: plan ahead to spend two days on the brining process.)
For the brine—2 days in advance: Roughly cut up the orange, lemongrass, and ginger into pieces. Smash garlic. Bring water to a boil and add garlic, ginger, chilies, lemongrass, orange, salt, sugar, soy sauce, and sweet soy sauce. Let it simmer until sugar and salt dissolve, about 10 minutes. Then remove from heat and refrigerate overnight.
For brining the turkey—1 day in advance: Place turkey and turkey neck into the chilled brine. Add more water, enough to cover the turkey. Cover with lid and refrigerate, 24 hours.
For the turkey: Preheat oven to 325 degrees F. Remove turkey from the brine and place it on a sheet tray lined with paper towels; allow it to dry and come to room temperature, 1 hour. Meanwhile, prepare the aromatics to be cooked with the turkey. Roughly chop the fennel with stems, onions, apples and ginger. Place aromatics around the turkey and inside the cavity. Next, make a compound butter by combining butter and sweet soy sauce. Rub a quarter of the butter all over the turkey. Discard the thermometer probe that comes with the turkey and replace it with a kitchen thermometer in the same spot or in the deepest part of the turkey. Roast the turkey to 160 degrees F, about 3 hours. (Note: it will continue to cook after it comes out of the oven.)
As the turkey cooks, baste it with more compound butter every 20–30 minutes.
When the kitchen thermometer in the turkey reads 160 degrees F, remove it from the oven and let it rest. The temperature will continue to rise slowly as it rests outside the oven. Let the turkey rest for 30 minutes before slicing and serving.