Add bourbon, lemon juice, simple syrup, and orange bitters to the shaker.
Shake hard for 10-12 seconds until the outside of the shaker feels cold.
Double strain into a chilled champagne flute or coupe glass.
Top with prosecco or champagne.
Express the orange peel oils over the drink by twisting it above the glass.
Drop the peel into the drink as garnish.
Notes
The drink should be served right away while the bubbles are fresh and active.Store simple syrup in the refrigerator for up to 2 weeks.Fresh lemon juice works best - bottled versions can taste bitter and artificial.A higher quality bourbon (90-100 proof) will give better results than basic mixing whiskeys.The cocktail can be made without alcohol by using ginger beer instead of prosecco and omitting the bourbon.