Start by washing the chicken and patting it dry. Place it in your cast iron skillet.
Preheat the oven to 350 degrees
Mix the butter, herbs de Provence, and garlic in a small bowl.
Cut the lemon into quarters.
Take a spoon and loosen the skin from the chicken breasts.
Sit the chicken up and pour half the butter mixture between the skin and breasts.
Rub the remaining butter mixture over the whole chicken.
Sprinkle generously with salt.
Fill the cavity with lemon quarters and fresh rosemary.
Tuck the wings under and tie the legs together.
Move the cast iron skillet to the preheated oven.
Bake for at least 1 hour and 30 minutes, basting the chicken with the juices at least 3-4 times during the cooking time. You do this by spooning the juices from the pan back over the chicken.
The chicken should be cooked to 165 degrees.
Remove it from the oven and let it cool for 15-20 minutes. The chicken is done and ready to serve.