In a large bowl, combine soy sauce, honey, hoisin sauce, rice vinegar, sesame oil, five-spice powder, garlic, ginger, and red food coloring if using. Mix well to create the marinade.
Add the chicken thighs to the marinade, ensuring they are well coated. Cover and refrigerate for at least 2 hours, preferably overnight for maximum flavor.
Preheat your grill or oven to 400°F. If using an oven, line a baking sheet with aluminum foil and place a wire rack on top.
Remove the chicken from the marinade, allowing excess marinade to drip off. Reserve the marinade for basting.
Grill the chicken for about 6-8 minutes per side, basting with the reserved marinade, until the chicken is cooked through and has a nice char. If using the oven, place the chicken on the wire rack and bake for 25-30 minutes, basting halfway through.
Once cooked, remove the chicken from the grill or oven and let it rest for 5 minutes. Slice and garnish with chopped green onions before serving.