Add Sugar Cube: Place 1 cane sugar cube in your Julep cup or Old Fashioned glass.
Add Bitters: Pour 5 dashes Angostura aromatic bitters over the sugar cube.
Add Soda Water: Measure and add 1 dash soda water on the sugar cube as well.
Muddle: Muddle the sugar cube to reduce it to powder and make sure it will fully dissolve later on.
Add Mint: Place 6-8 fresh mint leaves in one hand and gently smack it with the other, to release its aromas. Add the mint to the Julep cup or Old Fashioned glass.
Add Dark Rum: Measure and pour 2 oz Dark Rum into the glass.
Add Ice: Fill the glass three-quarters full with crushed ice.
Stir: Using a bar spoon or long stirrer, churn well to combine the ingredients.
Add Ice: Add a straw and top up with more crushed ice.
Garnish: Place a mint sprig into the glass and sprinkle some icing sugar on top for garnish. Serve immediately.