Basil-Grapefruit Cocktail by cucinagirl

3 basil leaves 
2 tablespoons basil-grapefruit simple syrup (strained) 
1 ½ oz. (citrus) vodka
splash of grapefruit juice 
club soda 
ice

In the bottom of an old-fashioned glass, muddle basil leaves.  Add simple syrup, vodka, and ice.  Top with club soda (several good splashes or to taste).  Stir.  Garnish with a grapefruit twist or slice and a sprig of basil, if desired.