Charterhouse

Chill a martini glass by filling it with ice water while you prepare the cocktail.

Add the Oloroso sherry, herbal liqueur, lime juice, and simple syrup into a cocktail shaker.

Fill the shaker with ice and securely close the lid.

Shake vigorously until the mixture is well chilled.

Discard the ice water from the martini glass and strain the cocktail into the glass.

Serve immediately.