Preheat the oven to 450°F.
Rinse the chicken, then dry it well with paper towels, inside and out.
Salt and pepper the cavity, as well as the exterior skin of the chicken
Mix your butter, mustard, garlic and fresh herbs together, and using your fingers, make a space between the skin and the chicken breast, being careful not to tear or rip the skin, and fill it with half your butter mixture. Rub the remaining butter mixture across the exterior of the bird and into the cavity.
Truss the bird. (Optional)
Place the chicken in a sauté pan or roasting pan and, when the oven is up to temperature, put the chicken in the oven.
Roast it until it's done, 50 to 60 minutes. Until internal temperature is 165 degrees.
Remove it from the oven and baste the chicken with the juices in the pan, let it rest for 15 minutes on a cutting board.
Carve and enjoy!