Add all the ingredients to your Boston Shaker except the Buckfast.
Dry shake (without ice) for 20 seconds to build up a foamy texture using the egg white.
Add ice to Boston and shake for a further 10-15 seconds.
Fill a rocks glass to the top with ice and strain your shaker ingredients into a rocks glass.
Drizzle the Buckfast to layer around the top of drink then garnish with grapes.
Sip and enjoy.