Preheat oven to 230°C. Line the base of a roasting tray with foil.
Wash chicken and dry thoroughly with paper towel. Stuff the chicken with lemon, garlic and sage.
Brush chicken generously with melted butter and sprinkle with pink salt flakes. Refrigerate uncovered for at least 1 hour.
Place chicken upside down on the roasting rack, tucking wings behind. Brush with more of the melted butter and sprinkle with salt.
Roast for 25 minutes. Turn chicken the right side up, tucking wings behind. Brush with more melted butter and/or pan juices, sprinkle with more salt. Cook for 20 minutes.
Turn up the heat to 260°C if your oven goes that high. And cook for 10 minutes or until brown and crispy. Rest for 20 minutes.
Serve with roast vegetables and garnish with fresh sage leaves.