Britomart's Pink Grapefruit Margarita

As I babbled about in the Hizzy, I recently had the most divine grapefruit margarita in a restaurant on Bainbridge Island. After much dedicated experimentation, I offer this recipe!

• 1 part tequila
• 3/4 part fresh-squeezed pink or red grapefruit juice
• slices of fresh red or pink grapefruit
• 3/4 part Cointreau
• 1/4 part fresh lime juice
• dash of seltzer water*
• coarse salt

Mix all of the ingredients (except the salt!). Rub a slice of grapefruit around the outside edge of a glass, then dip the glass into the salt. Add ice to the glass and pour in the mixed margarita ingredients. Garnish with the grapefruit slice.

* I'm a huge fan of champagne margaritas and was thinking earlier that a dash of champagne, instead of seltzer, would be delicious indeed.