Combine cream and milk in a medium saucepan. Add the leaves and ginger, and place over a medium-high heat. Bring to a boil, remove from heat, cover and let it steep for 40 minutes. Strainer out the leaves and ginger.
Whisk well the egg yolks, sugar and salt together until light in color and thick. Add a bit of the steeped mixture to the egg yolks, whisking constantly, to temper. Add the eggs to the mixture in the saucepan. On a low heat cook while stirring and scrapping the bottom until it coats the back of a wooden spoon. Stir in gin and rosewater.
Chill completely in refrigerator. Pour mixture into an ice-cream maker and freeze according to manufacturer's manual. Place in a covered container and freeze until firm.