Fill a tall glass with ice.
A highball or Collins glass works best.
Add 1.5 to 2 ounces of bourbon to the glass. Start with 1.5 ounces if you like a lighter drink.
Pour in 0.5 to 1 ounce of vanilla syrup. Use less if your soda is sweet; more if you’re using club soda.
(Optional) Add 1 to 2 tablespoons of heavy cream or half-and-half for a smooth, creamy texture.
Stir gently.
Top with 4 to 6 ounces of cream soda or club soda. Tilt the glass slightly and pour slowly to keep the fizz.
Stir once or twice with a long spoon to combine. Don’t over-mix—you want bubbles.
Garnish with a cherry, a twist of orange peel, or a pinch of grated nutmeg.
Serve immediately while it’s cold and effervescent.