The thing that sets this recipe apart from other grapefruit margaritas is a quick homemade grapefruit syrup using a few rinds from fresh grapefruit. Don't skip it!
I like to salt my rim for margaritas so run a lime around the edge of the glass and dunk it in coarse salt. This is an optional step.
If at all possible, use fresh grapefruit juice for these cocktails. It really makes a difference since there isn't too many ingredients!
Shake up the margarita and strain it into a glass with ice. CHEERS!