1
BEWARE, shaking with fizzy ingredients such as cider tends to be explosive.
2
Hence, use a still/less fizzy cider and hold both ends of your shaker firmly.
3
(If you have to hand, use a specially designed 'fizz' shaker such as Perlini, which is designed to be carbonated).
4
SHAKE all ingredients with ice and strain into glass (without ice).
5
Be sure to shake well to completely emulsify the egg.