Decorate the glass

• Melt the white chocolate and tint it with black food coloring.
• Brush or drizzle the chocolate down the inside of the glass to create a spooky dripping effect.
• Chill the glass until the chocolate sets.

Muddle the lime and mint

• Place the lime wedges, mint leaves and sugar in the glass.
• Muddle gently to release the juices and aromas without shredding the mint.

Build the cocktail

• Add the white rum and fill the glass with ice.
• Top up with soda water and stir gently.
• For a non-alcoholic version, leave out the rum and top up with Sprite or ginger ale instead.

Serve

• Garnish with a mint sprig and a lime wedge and serve immediately.