In a cocktail shaker filled with ice, combine gin, simple syrup and lemon juice. Shake vigorously.
Strain into a champagne flute. Top with champagne.
Garnish with a lemon wheel or twist. Serve immediately.
Notes
While this cocktail is pretty straightforward, here are a few tips to make it the most successful:
Always let the bottle of champagne chill well before you plan to use it. Cold champagne will make the flavors of your French 75 much better and will keep the drink crisp and cold! The carbonation of the champagne will also be bubblier when it is cold.
Serve each cocktail immediately after pouring. This is best practice to keep the champagne bubbly and the cocktail cold.
Try one of the many variations on this cocktail by substituting the classic gin for other spirits: