Preheat the oven to 425ºF/220ºC (or 400ºF/200ºC fan-assisted).
Prepare the chicken breast
Place the chicken in a Ziplock bag and tenderize the chicken with a meat mallet or rolling point. Do so gently until the chicken breasts have an even size and thickness (about 0.75 inches each)
Combine the spices, brown sugar, and melted butter in a small bowl and stir well. Add the marinade into the Ziplock bag and shake to cover each breast or rub it over each breast. Transfer to a baking dish.
How long to bake
Bake the chicken uncovered for around 15-18 minutes at 425ºF/220ºC (or 400ºF/200ºC fan-assisted). You can also choose to turn on the broiler for a few minutes at the end to enhance browning on the top.Larger chicken breasts (10oz+) will take between 20-25 minutes to cook.Check for doneness by inserting a thermometer in the thickest part of the chicken. The internal temperature must reach 165ºF/75ºC to be safe to eat.
Rest and serve
Take the chicken out of the oven. Set aside for 5-8 minutes, covered loosely with foil so the juices can settle.