In a bowl, combine the orange juice, olive oil, garlic, rosemary, honey, mustard, coriander, chili flakes, salt and pepper and stir to incorporate. Pat the chicken dry with paper towel and place it in a bowl or zip-top bag. Pour ¾ of the marinade overtop, reserving 1/4 for basting, toss the chicken to coat, cover and refrigerate 4 hours to overnight.
Preheat your grill or oven to 450F. Using butcher’s twine, tie the rosemary sprigs to the bottom of a wooden spoon to create a basting brush.
If using a grill, place the chicken skin side-up over indirect heat. Cook, basting with the reserved marinade every 15 to 20 minutes, until the thickest part of the breast registers between 150F and 155F, around 45 minutes. If using an oven, place the chicken on a roasting tray lined with a wire rack and cook, basting with the reserved marinade every 15 to 20 minutes, until the thickest part of the breast registers 155F, around 45 minutes.
If using a grill, carefully flip the chicken over and cook the skin side until it is lightly charred and the thickest part of the breast registers 160F, 5 to 10 more minutes. If using an oven, switch the setting to broil and cook until the skin is lightly charred and the thickest part of the breast registers 160F, 5 to 10 more minutes.
Transfer the chicken to a cutting board, baste once more with the reserved marinade and let it rest at least 10 minutes before carving. Serve the chicken with the Crunchy Fennel Slaw.