In a small pitcher mix the Vodka, lemon juice, sugar syrup and limoncello liqueur together until combined.
In 2-4 glass tumblers, evenly pour club soda over ice and top with Vodka mix.
Garnish each glass with a lemon slice & enjoy!
Homemade Sugar Syrup - In a small sauce pan boil equal parts water and granulated sugar on low-medium heat, stirring until sugar completely dissolves. Remove from stove and allow to come down to room temperature. Store in the refrigerator.