Prepare the rim: Mix 1 tablespoon sugar with a pinch of lemon zest on a small plate. Run a lemon wedge around the rim of a chilled coupe or rocks glass, then dip the rim into the sugar mixture.
Shake the base: In a cocktail shaker, add cranberry juice, lemon juice, and simple syrup with a handful of ice.
Shake for 10–12 seconds until chilled.
Strain and top: Strain into your prepared glass filled with fresh ice (or serve up in a coupe without ice). Top with sparkling water to taste.
Garnish: Add a lemon wheel and a few cranberries on a pick for a festive finish.
Taste and tweak: Add more simple syrup if you prefer sweeter, or more lemon for extra tang.