Step 1

Fill a cocktail shaker halfway full with ice. Add the vodka, triple sec, lemon juice, and simple syrup. Seal the shaker and shake vigorously for 30 seconds.

Step 2

Rub lemon slices around the rims of two coupes or martini glasses. Add sugar to a small plate; dip the rims of the glasses in sugar. Divide the vodka mixture between the two glasses. Garnish with lemon twists, if you like.