Add 4–5 ice cubes to a highball glass.
Pour 60ml of Tennessee whiskey over the ice.
Add 5ml of vanilla syrup.
Slowly pour 150ml of Coca-Cola down the side of the glass to preserve carbonation.
Gently stir once from the bottom to incorporate without losing fizz.
Serve immediately.
Use vanilla syrup instead of raw vanilla extract - extract contains alcohol and an astringent edge that can turn medicinal in a cold drink, while syrup integrates cleanly and sweetens in one step. Jack Daniel's is the obvious Tennessee whiskey call here, leaning into the name.
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