Prepare your martini glass: If you desire a sugared rim, run a lemon wedge around the rim of your chilled martini glass, then dip the rim into a shallow plate of granulated sugar. Set aside.

Combine ingredients: In a cocktail shaker, add the vodka, fresh lemon juice, simple syrup, and triple sec (or Cointreau).

Add ice: Fill the cocktail shaker about two-thirds full with ice cubes.

Shake well: Secure the lid tightly and shake vigorously for about 15-20 seconds until the shaker is well-chilled on the outside.

Strain and serve: Strain the mixture through a cocktail strainer into your prepared, chilled martini glass.

Garnish: Express the oils from a lemon peel over the drink by twisting it, then drop it into the glass or place it on the rim.