Mix [4 lt] of water with the ingredients for brining.
Butterfly the chicken (cut open through the breast plate and flatten).
Place the chicken in a deep pot and cover completely with the brine mix.
Place the chicken in the fridge and let it rest for 4 hours.
Pre-heat the oven to 350°F [175°C].
Take the chicken out of the brine and discard the brine.
Rinse the chicken to eliminate excess salt. Pat dry and brush all over with oil. Sprinkle with pepper.
Place the chicken skin side up on a a roast tray with rack (Amazon affiliate link).
If you have a meat thermometer
Roast until the thermometer reaches 71 °C [160 °F], start measuring at 1 hour.
If you don't have a meat thermometer
Roast for an hour, remove from the oven and turn around, the chicken will be ready when the juices run clear, return to the oven until there is no sign of blood.
Notes
Why not add some potatoes to the pan and make your dinner in just one step.