Nam yu is a type of fermented tofu that gets its vibrant red color from the red rice wine lees and spices used to make it. It's a prominent ingredient in char siu marinade to make it red.
For the chicken: Lay the chicken back-side up on a cutting board. Use kitchen shears to cut out the backbone. Flip the bird breast-side up, fold the wings under and press down with your palms to crack and flatten the breast plate. Transfer the chicken to a baking sheet and rub the salt and white pepper on the chicken to season it. Let sit, uncovered, for 30 minutes.
For the marinade: Puree the nam yu in a blender, then add it to a medium bowl. Add the Shaoxing wine, dark soy sauce, granulated sugar, grated ginger, light soy sauce and garlic and mix.
Coat the chicken with half of the marinade. Refrigerate the chicken, uncovered on the baking sheet or in a ziptop bag, for at least 4 hours and up to 24 hours.
Add the remaining marinade to a small saucepan with the honey. Bring to a boil over medium-high heat, lower to a simmer and simmer until reduced by half, 5 to 8 minutes. Reserve for basting.
For the ginger-scallion relish: Puree the ginger, grapeseed oil, chives and salt in a blender, stopping and scraping down the sides once, until pulverized to a paste.
Heat a sauté pan over medium heat. Add the ginger-chive paste and scallion greens and cook until the sauce turns green, 3 to 5 minutes.
About an hour before cooking the chicken, remove it from the refrigerator.
Preheat the oven to 400 degrees F. Line a baking sheet with aluminum foil and place a wire rack on top.
Place the chicken on the rack, spread it out and roast, basting occasionally with the reduced marinade toward the end of cooking, until crispy, charred and cooked through, 40 to 50 minutes, depending on size of your chicken.
Allow the chicken to rest about 20 minutes, then place on a serving platter with the ginger-scallion relish.
