Preheat your oven to 180°C / 356°F and place the rack in the middle.
Dry your chicken properly using paper towels. Dry around the chicken and don't forget to dry it on the inside, you want the spice rub to stick properly onto the chicken without any damp. If your chicken has any giblets inside, remove them and if you want to trim off the wing tips you can do that, otherwise simply dry it off.
Now you can add the spices into a bowl and pour in the olive oil, mix it together and rub it over the chicken, inside and around, well coated (leave a little behind for the potatoes). I work on top of a piece of foil not to avoid the mess but to catch any of the drippings because that's all flavor! You can use a brush to brush the spice and olive oil mix on the chicken but you also have to use your hands, they work much better. Rub everything on the chicken making sure to also get the spice rub inside the chicken. Use the brush to collect the last bits and smooth it over. Now you can take the foil that you were working on, pour any last drippings over the chicken and place the foil in the pan. This is when we're using the foil for less clean up later! Place the rack over the foil and set your chicken over the rack.
Add the potatoes into a bowl, pour the remaining spice mix over and use your hands to get the mix in there.Add the potatoes around the chicken.
Bake your chicken for 20 minutes per 500 grams. Use your timer and after the first 20 minutes, take it out and pour part of the melted butter over. Return the chicken to the oven to continue roasting for the remaining time. For the last 20 minutes remove the chicken, pour a little more of the melted butter over the chicken. Increase the heat to 230 for 15 5o 20 minutes to crisp up the skin.Let your chicken rest for 15 minutes before slicing into it.