Everyone is looking for this chicken recipe! Simple and delicious

Ingredients:
an entire chicken: 1 pc
soft butter: 200 g (7.1 oz)
garlic: 20 g (0.7 oz)
black pepper: 4 g (0.1 oz)
salt: 7 g (0.2 oz)
sweet paprika: 4 g (0.1 oz)
lemon zest: 5 g (0.2 oz)
rosemary: 20 g (0.7 oz)
potatoes: 1 kg (2 lb)
dried rosemary: 5 g (0.2 oz)
black pepper: 5 g (0.2 oz)
salt: 5 g (0.2 oz)
vegetable oil: 20 ml (0.7 fl oz)