Prep Glass: Fill a coupe glass with ice. Set it aside.
Add Lemon Juice: Pour ¾ oz fresh lemon juice into the shaker.
Add Cointreau: Add 1 oz Cointreau.
Add Bourbon: Finally, add 2 oz Bourbon to the mix.
Rim Glass: Discard the ice inside the coupe glass and prepare the sugar rim. To do so, use a lemon slice to slightly wet the rim of the glass. Then, delicately press the edge of the glass into a plate filled with sugar.
Shake Well: Fill the shaker with ice, close it, and give it a good shake (10-15 seconds).
Strain: Using both the cocktail strainer and the fine strainer, strain the mixture into the coupe glass.
Garnish: Express a lemon zest on top of the drink to release its oils and drop in the glass or discard it. Serve immediately.