Step 1In a pot heated over medium-low heat, toast the mustard seeds just until they start to pop, 2 to 3 minutes. Add the cider and stir in the salt, ½ cup honey and bourbon. Add the crushed rosemary and continue to heat, stirring, until the salt is dissolved. Remove from heat and cool to room temperature.
Step 2Place the chicken in a non-reactive container and pour over the brine. Place a plate over the chicken to weigh it down to keep it submerged. Cover and refrigerate overnight.
Step 3The next morning, remove the chicken from the brine and dry with paper towels. Place the chicken, uncovered, on a rack and refrigerate until about 1 hour before cooking. Remove the chicken and leave it at room temperature for an hour to take the chill off.
Step 4Heat the oven to 400 degrees. Truss the chicken if you’d like, and place on a rack on a rimmed baking sheet or shallow roasting pan. Stir together the melted butter and remaining 2 tablespoons honey. Brush the honey-butter over the chicken. Roast the chicken for 15 minutes.
Step 5Lower the heat to 350 degrees and continue roasting until a thermometer inserted in the thickest part of the thigh reaches 165 degrees. Remove and set aside 15 to 20 minutes before serving.