Chill your glass and ingredients. Pop a highball or Collins glass in the freezer for 5–10 minutes. Keep the club soda cold so the drink stays extra fizzy.
Add ice to the glass. Fill the chilled glass with fresh ice, about three-quarters full.
Measure the bourbon. Pour in 1.5 to 2 ounces of bourbon, depending on how strong you like it.
Sweeten with vanilla. Add 0.75 to 1 ounce of vanilla syrup.
Start lighter if your bourbon runs sweet.
Add cream. Pour in 0.5 to 1 ounce of heavy cream or half-and-half. The more you add, the richer it gets.
Top with fizz. Slowly add 4–6 ounces of club soda. Pour against the side of the glass to preserve bubbles.
Gently stir. Use a bar spoon to lift from the bottom with two or three slow turns.
Don’t over-stir or you’ll lose carbonation.
Taste and adjust. If you want more sweetness, add a splash more syrup. For more richness, a bit more cream. For more sparkle, a touch more club soda.
Garnish and serve. Top with whipped cream and a cherry for a soda shop vibe, or keep it simple with an orange twist.
Serve immediately.